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# NCV 3 Mathematical Literacy Hands-On Support Slide Show - Module 3

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### NCV 3 Mathematical Literacy Hands-On Support Slide Show - Module 3

1. 1. Mathematical Literacy 3
2. 2. Module 3: Patterns and relationships
3. 3. Module 3: Patterns and relationships <ul><li>At the end of this module you will be able to: </li></ul><ul><ul><li>Identify and extend patterns for different relationships in the workplace </li></ul></ul><ul><ul><li>Identify and use information from different representations of relationships to solve problems in the workplace </li></ul></ul><ul><ul><li>Translate between different representations of relationships found in the workplace </li></ul></ul>
4. 4. 1. IDENTIFY AND EXTEND PATTERNS FOR DIFFERENT RELATIONSHIPS IN THE WORKPLACE <ul><li>At the end of this outcome you will be able to: </li></ul><ul><ul><li>Investigate and extend numerical and geometric patterns and identify trends in data </li></ul></ul><ul><ul><li>Describe patterns and trends in words and/or through formulae </li></ul></ul><ul><ul><li>Generate patterns from descriptions of them </li></ul></ul>
5. 5. Arithmetic patterns <ul><li>A pattern can be formed by adding a constant number. </li></ul><ul><li>When you were in primary school you had to learn the arithmetic tables. </li></ul><ul><li>First you were taught that: </li></ul><ul><li>1 x 2 = 2 </li></ul><ul><li>2 x 2 = 4 </li></ul><ul><li>3 x 2 = 6 </li></ul><ul><li>4 x 2 = 8 </li></ul><ul><li>5 x 2 = 10 etc… </li></ul><ul><li>Then you were taught to count in two’s: 2; 4; 6; 8; 10; 12; 14 etc….. </li></ul><ul><li>Or in three’s: 3; 6; 9; 12; 15; 18 etc….. </li></ul>
6. 6. Arithmetic patterns <ul><li>These primary school arithmetic tables are an illustration of constant difference patterns in numbers. </li></ul><ul><li>The pattern in the two times table, is a difference of two each time. </li></ul><ul><li>Similarly, the pattern in the nine times table, is to add nine each time to get the next number. </li></ul><ul><li>The relationship between the input value and the value can be summarised in a formula or equation. </li></ul><ul><li>For this table the formula is: y = 2x </li></ul><ul><li>In words, this formula means that the one variable (x in this case), times a constant number (the 2 in this case), will give you the other variable (y in this case). </li></ul>
7. 7. Arithmetic patterns <ul><li>Notice that the output values show a plus-four pattern and also notice that there is a constant way of getting from the input value to the output value: </li></ul><ul><li>If 4 people can sit at one table, then 8 people can sit at 2 tables and 12 people at three tables. </li></ul><ul><li>Let’s tabulate the information, and then you write the formula! </li></ul>
8. 8. Activity 1 <ul><li>1. A baby weighs on average 3400g at birth, and increases its birth weight by 650g per month. Now fill in the table and write a formula for the calculation of the output value which is the weight of the baby. </li></ul><ul><li>a. Formula: Weight of baby = </li></ul><ul><li>b. Complete the table </li></ul>0,65 x + 3,4 3,4 4,05 4,7 5,35 6 6,65 7,3
9. 9. Activity 1 <ul><li>2. a. Formula for the cost of face bricks </li></ul><ul><li>b. Complete the table </li></ul>y = 3000 x R3000 6000 9000 12000 15000 18000 21000
10. 10. Activity 1 <ul><li>2. a. Formula for the cost of face bricks </li></ul><ul><li>b. Complete the table </li></ul>y = 3000 x R3000 6000 9000 12000 15000 18000 21000
11. 11. Activity 1 <ul><li>Currency conversion: £1 = 14,1916 rand (ZAR) </li></ul><ul><ul><li>Formula: </li></ul></ul>Number of pounds times 14,1916
12. 12. Geometric patterns <ul><li>Another kind of pattern is where there is a constant ratio involved between two consecutive numbers of the pattern. This means that every next number in the sequence divided by the previous number will give the same constant value. </li></ul><ul><li>Put in other words, each number can be multiplied by a constant number to get the next number in the sequence of numbers. </li></ul><ul><li>  Example: 2; 4; 8; 16; 32; 64 etc….. </li></ul><ul><li>Once again, there are two ways of looking at the pattern evident from the relationship. </li></ul><ul><li>Each output value is multiplied by 2 to get the next number in the pattern. </li></ul><ul><li>Each output value can also be seen as two to the power of the particular input value. </li></ul><ul><li>The formula is now: y = 2 x </li></ul>
13. 13. Geometric patterns <ul><li>If you put R50 000 in a fixed deposit account in the bank, you are actually lending your money to the bank and it is in your interest to be paid for this action. </li></ul><ul><li>The bank pays you interest on your money. </li></ul><ul><li>One South African bank pays 10% per year compound interest. All banks have slightly different interest rates. </li></ul><ul><li>The calculation of this compound interest forms a geometric pattern. </li></ul><ul><li>The full starting amount is R50 000; this is called 100%. </li></ul><ul><li>Add the interest of the year to this full starting amount: 100% + 10% = 110% = which is the same as 1,1 </li></ul><ul><li>Then, each year the amount in the bank must be multiplied by 1,1. </li></ul><ul><li>The 1,1 is the constant ratio. </li></ul><ul><li>Year 1: R5 000 x 1,1 = R5 500 </li></ul><ul><li>Year 2 : R5 500 x 1,1 = R6 050 </li></ul><ul><li>Year 3: R6 050 x 1,1 = R6 655 etc….. </li></ul>
14. 14. Activity 2 <ul><li>1. Write down five numbers that you think should logically follow on the numbers in the following sets. </li></ul>
15. 15. Activity 2 <ul><li>Write down what you see as the constant difference or the constant ratio in each of the above sets of numbers. </li></ul><ul><ul><li>A times 2 pattern </li></ul></ul><ul><ul><li>A plus 350 pattern </li></ul></ul><ul><ul><li>A plus 250 pattern </li></ul></ul><ul><ul><li>A times 1,05 pattern </li></ul></ul><ul><ul><li>A ÷ 2 pattern </li></ul></ul>
16. 16. Activity 2 <ul><li>Order the following numbers to form a patterned sequence of numbers from the smallest number first to the biggest number last, i.e. ascending order. </li></ul><ul><ul><li>0,3358; 0,3433; 0,3458; 0,3383; 0,3483; 0,3508; 0,3408; </li></ul></ul><ul><ul><li>13 000 thousand; 12,5 million; 0,014 billion; 12 000 000; 1,35 x ; </li></ul></ul><ul><ul><li>11h37; 10h52; 11h37; 11h22; 10h37; 11h07; </li></ul></ul>0,3358; 0,3383; 0,3408; 0,3433; 0,3458; 0,3483; 0,3508 12 000 000; 12,5 million; 13 000 thousand; 0,014 billion; 1,35 x 10 7 10h37; 10h52; 11h07; 11h22; 11h37; 44h49
17. 17. Activity 2 <ul><li>If a certain bank decides that annual interest will be paid at a compound rate of 10% of the amount deposited, (i.e. ), calculate the amounts in the bank after one, two, three and four years. </li></ul>
18. 19. Activity 2 <ul><li>A friend tells you that he will loan you money at a simple interest rate of 5% p.a. i.e. 0,05 of the amount per year. Fill in the table: </li></ul>
19. 21. Activity 2 <ul><li>Fill in the missing numbers according to the pattern: </li></ul>
20. 23. Case study <ul><li>Bongani has started a small paving business after doing a road construction learnership. He has to decide how many men are necessary to do the job most efficiently. He estimates that five men will take 30 days to complete a section of pavement with concrete and bricks. </li></ul>
21. 24. Case study <ul><li>How many one-man working days are involved? </li></ul><ul><li>Will six men take less or more time to complete the job? </li></ul><ul><li>Draw up a table of the information with the number of men as input value and the number of days as output value. The one-man working days must remain constant. </li></ul>Each man contributes six working days. In other words, each man does one fifth of the work. One man will take 5 x 30 days to do the work, i.e. 150 days. Less time
22. 25. Case study <ul><li>Give an equation for the graph </li></ul><ul><li>Calculate how many days it will take 15 men to complete the job </li></ul><ul><li>Sketch the graph </li></ul><ul><li>Read from the graph how many men are necessary to complete the job in five days </li></ul>y = 150 ÷ x Ten days 30 men will complete the job in 5 days
23. 27. Case study <ul><li>It is important for Bongani to be in contact with the contractor of the job. Therefore he has to have enough airtime on his cell phone. </li></ul><ul><li>He buys a R110 pay-as-you-go air-time voucher. He makes his work calls in peak time when calls will cost him R2 for the first minute and thereafter R1 per 30 seconds. </li></ul>
24. 28. Case study <ul><li>Give an equation for the calculation of cell phone cost per call: </li></ul><ul><li>Cost of call = </li></ul><ul><li>Draw up a table for Bongani so that he can sketch a graph from which to look up cost of calls for different duration of calls. </li></ul>x + 2 (x = number of 30second periods)
25. 29. Case study <ul><li>Draw up a table to show an inverse relationship between duration of call and number of calls possible for the R110. </li></ul>
26. 30. Case study <ul><li>3. After two years of hard work Bongani has put together R5 000 and invests it in his bank’s money market account at an interest rate of 11,5% compound interest. The money is compounded each month. </li></ul>5606,29 6286,10 7048,34
27. 31. Direct and inverse relationships <ul><li>Examples of a direct relationship </li></ul><ul><ul><li>As the volume of petrol that you put into the car’s tank increases, so does the amount of money that you have to pay. We say that the cost is directly related or dependent on the litres of petrol put into the tank. </li></ul></ul><ul><ul><li>As the distance that you travel increases, so do both the time, as well as the cost of the journey increase. </li></ul></ul><ul><li>Examples of an inverse relationship </li></ul><ul><ul><li>As the petrol price shows a steady increase over the years, the volume of petrol that you can purchase for the same amount, shows a steady decrease. </li></ul></ul><ul><ul><li>The pattern is: The input value times the output value gives a constant number </li></ul></ul>
28. 32. Trends <ul><li>Series 1 – slight positive trend </li></ul><ul><li>Series 2 – stronger positive trend </li></ul><ul><li>Series 3 – negative trend </li></ul><ul><li>Series 4 – constant trend </li></ul>
29. 33. Inverse relationships
30. 34. Activity 3 <ul><li>State whether the following tables show a direct or an inverse relationship. Complete the tables. </li></ul>Inverse
31. 35. 1,67 Inverse Direct Direct 10 5 3,5 2,5
32. 40. Activity 3 <ul><li>Look at the table on cash loans: </li></ul><ul><ul><li>Is there a constant difference or a constant ratio between the loan repayment amounts for the two different payment options? </li></ul></ul>Constant ratio of more or less 30% for the 24 month option. However it is higher for the R10 000 loan at 35%. Calculation : 1087 x 24 = 26088; increase is 6088; increase percentage = 6088÷20000 = 30,44% For the 60 month option the percentage increase is 78% (once again it is higher for the smaller loan amount).
33. 41. Activity 3 <ul><li>Is there a direct or inverse relationship between the loan repayment amounts for the two different payment options? </li></ul>The longer the payment time the smaller the monthly payment amount, i.e. an inverse relationship.
34. 42. Activity 3 <ul><li>Calculate how much a loan of R30 000 will cost if repaid over 5 years. </li></ul>It will cost 53280 – 30000 = R23280.
35. 43. Activity 3 <ul><li>Calculate the % increase that the cost of the loan is with regard to the loan amount. </li></ul>23280 ÷30000 x 100 = 77,6%
36. 44. Activity 3 <ul><li>Look at the following table on a cash loan of R12 000. Monthly repayment options dependent on repayment period. </li></ul>
37. 45. Activity 3 <ul><li>Is there a positive or negative relationship between the repayment period and the monthly repayment amounts? </li></ul>Negative: As the months increase the monthly payment amount decreases
38. 46. Activity 3 <ul><li>b. Complete the table with the actual repayment amount as well as the cost of the loan for the different time periods. </li></ul>
39. 47. Activity 3 <ul><li>Is it better to repay within 12 months or within 36 months? Give a reason for your answer. </li></ul>Within 12 months: the shorter the payment period, the smaller the cost of the loan.
40. 48. Putting patterns into words and the other way around <ul><li>Mathematical information can be presented as follows: </li></ul><ul><li>A simple flow diagram: </li></ul><ul><li>Input value x 0,2 + 50 = Output value </li></ul><ul><li>This can also be written as an algebraic formula: </li></ul><ul><li>y = 0,2x + 50 </li></ul><ul><li>The value that you put into the formula is the independent variable (usually called the x-value) and the value that is produced by the formula, is the dependent variable (usually called the y-value). The dependent value depends on the independent value that is fed into the formula. </li></ul>
41. 49. Putting patterns into words and the other way around <ul><li>Put into words y = 0,2x + 50 would read: </li></ul><ul><li>A certain number must be multiplied by 0,2 and 50 must be added to the </li></ul><ul><li>answer to obtain the output value or answer. </li></ul><ul><li>Put in other words it could mean: A waitress at a 5-star restaurant earns a basic amount per day of R50 plus 20% commission on the total income that she generated </li></ul>
42. 50. Activity 4 <ul><li>Complete the flow diagrams and write in words what the flow diagrams mean: </li></ul><ul><li>Earnings per day of clerks at IT retail shop: </li></ul>
43. 51. Activity 4 <ul><li>b. Sammy’s Private Taxi rate: </li></ul>
44. 52. Activity 4 <ul><li>2. Complete the following tables according to the given formula’s or written instructions: </li></ul><ul><li>y = 5x - 2 (Also write this instruction in words.) </li></ul>
45. 53. Activity 4 <ul><li>c. Complete the operating instructions, give the correct formula and then complete the tables : </li></ul><ul><li>Divide the x-value by ______ and add ______ to the answer: </li></ul><ul><li>Formula:______________ </li></ul>5 8 y=x/5 +8
46. 54. Activity 4 <ul><li>c. Multiply the x-value by and subtract from the answer. </li></ul><ul><li>Formula: </li></ul>3 2 y = 3 x - 2
47. 55. Activity 5 <ul><li>Sketch five graphs of the information in Activity 4 </li></ul>
48. 60. Relationships <ul><li>Continuous relationship </li></ul><ul><li>Discrete relationship </li></ul><ul><li>Step-relationship </li></ul><ul><li>Piece-wise relationship </li></ul>
49. 61. Activity 6 <ul><li>1. Before Bongani started his own business he used to work for a construction business. He worked out of town and had to do a lot of travelling for his work. He was given a travel allowance from his employer for expenses. </li></ul><ul><li>Represent on graph paper the information in this table of car value vs. deductions on fuel cost and wear and tear on the car. </li></ul>
50. 64. Activity 6 <ul><li>He also had to pay income tax </li></ul><ul><ul><li>Represent on graph paper the relationsip between the individual income tax bracket vs tax payment </li></ul></ul><ul><ul><li>The tax threshold for people under 65 years of ages in 2008 = R43 000. What does this mean? </li></ul></ul>If you earn less than R43 000, you don’t have to pay tax
51. 66. Assignment <ul><li>Each learner must include the chosen investigation in his/her portfolio of evidence. </li></ul><ul><li>Delegate the work, e.g. for question 1: </li></ul><ul><li>One person in the group can do the research on the internet, a second can organise the information, a third and fourth person can represent and finalise the answers. </li></ul><ul><li>Decide within the groups how to delegate the work for numbers 2 and 3. </li></ul><ul><li>Do one of the following investigations: </li></ul><ul><li>1. Investigate the cost of touring by long distance bus in South Africa. </li></ul><ul><li>a. In a table compare the prices of two different bus operators for different distances. </li></ul><ul><li>Examples of websites: www.eljosa.com or www.citiliner.co.za </li></ul><ul><li>Represent the comparative information on graph paper. </li></ul><ul><li>  </li></ul>
52. 67. Assignment <ul><li>Ask the following people how they calculate the cost of their products: </li></ul><ul><ul><li>Your local taxi operators. </li></ul></ul><ul><ul><li>Your local supermarket. </li></ul></ul><ul><ul><li>A restaurant or fast food outlet in your vicinity. </li></ul></ul><ul><ul><li>Your bank. </li></ul></ul><ul><ul><li>Your cell phone provider. </li></ul></ul><ul><li>  </li></ul>
53. 68. Assignment <ul><li>3. Your cell phone may either be on a contract or might have been bought cash. </li></ul><ul><li>Give the table of your own cell phone contract or your own cell phone pay-as-you-go costs. </li></ul><ul><li>Represent this information on a graph and make a few predictions about cell phone usage of the group. </li></ul>
54. 69. Assignment <ul><li>Take the pulse rate of 50 people with ages spread out evenly between 18-60. This is group work – delegate the taking of pulse rates so that each person only has to take the pulse rate of a few people. </li></ul><ul><li>a. Plot the information on a graph </li></ul><ul><li>b. Describe the trend of pulse rates </li></ul>
55. 70. 2. IDENTIFY AND USE INFORMATION FROM DIFFERENT REPRESENTATIONS OF RELATIONSHIPS TO SOLVE PROBLEMS IN THE WORKPLACE <ul><li>At the end of this outcome you will be able to: </li></ul><ul><ul><li>Identify and select information from different representations of relationships to solve problems </li></ul></ul><ul><ul><li>Use and develop formulae with confidence </li></ul></ul>
56. 71. Activity 7 <ul><li>Study the pit chart and answer the questions that follow: </li></ul>
57. 72. Activity 7 <ul><li>What is the subject of the pie chart? </li></ul><ul><li>Which country has the largest global sale of organic foods? </li></ul><ul><li>What does (\$11 bill.) mean? Write the figure out in full. </li></ul><ul><li>What does (\$725 mill.) mean? Write the figure out in full. </li></ul>Global sales of organic foods United States of America \$11 000 000 000 \$725 000 000
58. 73. Activity 7 <ul><li>Which country has the smallest sale of organic foods? </li></ul><ul><li>How many countries are represented in this pie chart? </li></ul><ul><li>Under which section would you look for African sales of organic food? </li></ul><ul><li>Why are African countries not represented separately on this pie chart? </li></ul>Japan Nine Rest of the world Sections too small
59. 74. Activity 7 <ul><li>2. Study the bar graphs and answer the questions that follow: </li></ul>
60. 77. Activity 7 <ul><li>Which cell phone brand is the most popular overall? </li></ul><ul><li>Which cell phone brand is the most popular amongst young adults? </li></ul><ul><li>Which are the four least popular cell phone brands in the four bar graphs? Have you ever heard of any of them? </li></ul><ul><li>What do you think is represented on the horizontal axis and why does the newspaper not find it necessary to show this on the sketches? </li></ul><ul><li>What 78% percentage of tweens gives Samsung the highest rating? </li></ul>Nokia Nokia Alcatel, Sagem, Panasonic, Siemens Percentage and it is not shown because it is very obviously from the axes which runs from zero to 90 78%
61. 78. Activity 7 <ul><li>Explain in words how the distance grid works. Use three examples from the grid to illustrate your explanation. </li></ul>
62. 79. Activity 8 <ul><li>Solve the following equations by logic </li></ul><ul><ul><li>4t = 24 -> What is the value of “t”? </li></ul></ul><ul><ul><li>x / 1000 = 200 -> What is the value of “x”? </li></ul></ul><ul><ul><li>V = (8) (16) (7) -> What does V stand for? </li></ul></ul><ul><ul><li>1500 = (3) (5) (h) -> What does the “h” stand for? </li></ul></ul><ul><ul><li>P = 2(L + b) -> If P = 48 and L = 15 what is b? </li></ul></ul>t = 24 ÷ 4 = 6 x = 1000 x 20 = 200 000 Volume = 897 cubic units Height = 1500 ÷ 15 = 100 48 = 2(15 + b) Therefore 24 = 15 + b Breadth = 9 units
63. 81. Activity 9 <ul><li>Select the correct formula from the given table and then calculate using the given substitution values </li></ul><ul><li>a. SI if P = R3 000; t = 6 years and r = 17% </li></ul><ul><li>b. S if d = 40km and t = 2,5 hours </li></ul><ul><li>c. Area of a circle if r = 25cm </li></ul>SI = 3060 Speed = 16 km/h Area = 1963,49cm 2
64. 82. Activity 9 <ul><li>Circumference of a circle if r = 25 cm </li></ul><ul><li>V if L = 10 ; b = 7 and h = 25 </li></ul><ul><li>P if L = 75 and b = 25 </li></ul><ul><li>Degrees C if degrees F = 212 </li></ul>157,08cm Volume = 1750 P = 200 units C = 99,999 degrees Fahrenheit
65. 83. Activity 9 <ul><li>Select the correct formula from the given table to calculate the following by substituting the given values: </li></ul><ul><ul><li>Calculate the average speed of an aircraft that takes 3 hours to fly 1 800 km. </li></ul></ul><ul><ul><li>Calculate the circumference of a circle with radius 1,5m. </li></ul></ul><ul><ul><li>Convert 76 degrees Fahrenheit to degrees Celsius </li></ul></ul>Speed = 600 km/h Circumference = 9,42477 m Degrees Celsius = 24,4
66. 84. Activity 9 <ul><li>What is the total external surface area of a cylinder, which has a radius of 25cm and a height of 35 cm? </li></ul><ul><li>How many cubic metres of water is there in a swimming pool which is 15 metres long, 5 metres wide and 2 metres deep? </li></ul><ul><li>If you borrow R800 from a friend and he charges you simple interest at a rate of 6% per year, calculate the amount of interest that you have to add to the initial amount when repaying your friend after 5 years. </li></ul><ul><li>What is the length of fencing that a farmer has to buy to fence his farm, which is 2000 m long and 850 m wide? </li></ul>Total external surface area = 9424,77cm² Volume = 150m³ SI = R 240 Perimeter = 5700m
67. 85. TRANSLATE BETWEEN DIFFERENT REPRESENTATIONS OF RELATIONSHIPS FOUND IN THE WORKPLACE <ul><li>At the end of this outcome you will be able to: </li></ul><ul><ul><li>Convert representations of relationships from one form to another to reveal features of patterns and relationships </li></ul></ul><ul><ul><li>Select and develop representations of relationships to solve a problem and/or communicate/illustrate a result </li></ul></ul>
68. 86. Converting representations <ul><li>There are many different ways to represent data. You have heard of most of them. </li></ul><ul><ul><li>Words </li></ul></ul><ul><ul><li>Tables </li></ul></ul><ul><ul><li>Straight line graphs </li></ul></ul><ul><ul><li>Broken line graphs </li></ul></ul><ul><ul><li>Bar graphs </li></ul></ul><ul><ul><li>Scatter graphs </li></ul></ul><ul><ul><li>Histograms </li></ul></ul><ul><ul><li>Pie charts </li></ul></ul><ul><ul><li>Stem-and-leaf diagrams </li></ul></ul><ul><ul><li>Pictograms </li></ul></ul>
69. 87. Activity 10 <ul><li>1. From the broken line graphs below, answer the following questions: </li></ul><ul><ul><li>What is the subject of the presentation? </li></ul></ul><ul><ul><li>What is the variable on the vertical axis? </li></ul></ul><ul><ul><li>Make a table from the information in the sketch. </li></ul></ul>Annual hours worked per person Hours worked
70. 89. Activity 10 <ul><li>Make a bar graph from the information in the table. </li></ul>
71. 90. Activity 10 <ul><li>Why do you think that the line for France suddenly dips in 1938? </li></ul><ul><li>Name two mistakes which were made in this representation </li></ul>War was imminent – no normal work was done then Years on the horizontal axis not evenly spread. No title to the graph
72. 91. Selection of representations <ul><li>To sketch a line graph or a bar graph you need to know what the number line is. </li></ul><ul><li>For learners who might not know what a number line is: </li></ul><ul><li>This is the number line : </li></ul><ul><li>- ..….. –8 –7 –6 –5 –4 –3 –2 –1 0 1 2 3 4 5 6 7 8 ……. </li></ul><ul><ul><li>The number line is similar to a thermometer which but lies horizontally. The negative (small) numbers always lie to the left of zero and the positive numbers to the right of zero. Note that negative 2 (or –2), is smaller than negative 1 (or –1). Therefore the further to the left on the negative side, the larger the digits but the smaller the value of the digits. </li></ul></ul><ul><ul><li>The symbol lying at the extreme left and right-hand sides of the line, represents infinity which means indefinitely (undefined), large or small . </li></ul></ul><ul><ul><li>The dots on the sketch indicate that the numbers continue to negative infinity on the left, and to positive infinity on the right. </li></ul></ul><ul><ul><li>To conclude, the number line always runs from the extremely small numbers on the left to the extremely large numbers on the right . </li></ul></ul><ul><ul><li>The numbers printed on this specific number line are all integers or whole numbers . However, all the innumerable fractions between the whole numbers are present, just not marked for you to see. </li></ul></ul>
73. 92. Drawing a line graph <ul><li>The Cartesian co-ordinate system consists of a grid system with a vertical axis called the y-axis and a horizontal axis called the x-axis. </li></ul><ul><li>x and y values are co-ordinated i.e. brought together on this grid system </li></ul><ul><li>Each axis represents a number line such as a thermometer – note that there is a negative side to each number line. </li></ul><ul><li>The intersection of the x- and y-axes is called the origin. </li></ul><ul><li>The position of a point on a plane is denoted by an ordered pair of numbers called x and y co-ordinates (x;y). </li></ul>
74. 94. Activity 11 <ul><li>Study the graph below and describe the trends in the 4 series of data in this compound bar chart </li></ul>
75. 95. Activity 11 <ul><li>Series 1 – Positive or increasing trend </li></ul><ul><li>Series 2 – Positive or increasing trend </li></ul><ul><li>Series 3 – Negative or decreasing trend </li></ul><ul><li>Series 4 – Constant function </li></ul>
76. 96. Activity 12 <ul><li>Select a representation for the information in Activity 4 question 1. </li></ul><ul><li>Then see if you have not already sketched it in Activity 5, </li></ul><ul><li>If not, sketch it. </li></ul>
77. 98. Activity 12 <ul><li>2. a. Investigate the following situations and decide on one or two good ways to represent the information: </li></ul><ul><li>b. Sketch one of these representations </li></ul><ul><li>Bongani’s monthly expenses/budget </li></ul><ul><li>Rent R2 500 </li></ul><ul><li>Food and household goods R2 000 </li></ul><ul><li>Travel costs (personal) R 500 </li></ul><ul><li>Cell phone (personal) R 450 </li></ul><ul><li>Cigarettes R 250 </li></ul><ul><li>Lotto R 160 </li></ul><ul><li>Clothes R 450 </li></ul><ul><li>Other R 350 </li></ul><ul><li>  </li></ul>
78. 101. Activity 12 <ul><li>Basic rule of tips at coffee shop or restaurant </li></ul><ul><li>Total bill between R30 and R100 Multiply the first digit by two. </li></ul><ul><li>Example: Bill of R56,24 leave as tip 5 x 2 = R10 </li></ul><ul><li>You will be tipping at an average rate of 16%. </li></ul>
79. 102. Activity 12 <ul><li>Complete the columns for 15% and 20%. </li></ul><ul><li>Draw three graphs on the same set of axes for the last three columns with regard to the size of the bill. </li></ul><ul><li>What could you call the graph for the “rule of two” -column? </li></ul><ul><li>Why would a person want to use this method of tipping? </li></ul>A step by step function – It remains constant for a while and then steps up Quicker and easier
80. 105. Summative assessment <ul><li>Beverley is personal office assistant for the managing director of a mail order vitamin factory. The business delivers to private persons or retail outlets such as pharmacies and large department stores. Beverley has to calculate the mailing costs of all parcels that leave the factory. </li></ul><ul><li>She has been given the following cost tables: </li></ul>
81. 107. Large parcel rates (all prices shown in Rand)
82. 108. Speed services counter to counter or to door – parcels (all prices shown in Rand)
83. 109. Questions <ul><li>Make a compound bar graph of the data in the first table – surface mail and air mail letter rates. </li></ul><ul><li>Do you think that the bar graph will save her time? Explain your answer. </li></ul><ul><li>What kind of graph should Beverley draw up for the table on large parcel rates? What use could this graph have for Beverley? </li></ul><ul><li>Draw two graphs on the same set of axes for the speed services table. </li></ul><ul><li>Do the last two graphs show consistent trends? Explain your answer. </li></ul><ul><li>Can a pie chart be used for any of the supplied information? Explain your answer. </li></ul>Straight-line graphs