1. November 22, 2013

2. Notes:
 Complete Guides to
a) Fractions b) Simplifying
Posted @v6 math (pages)
 Tuesday: Test on Simplifying (prime factorization,
GCF, and factoring)

3. Warm-Up:
2.
3 3/7 + (-2 3/8)
2
Simplify:
4.
10m – 15n
5
7. 15x2 + 21x6
5.
20a6b5
6.
45
10x – 10
35a2b3
2 = ?_
3
18
36__ =
4 (x - 8)
9__
2(x – 1)
?__
(x - 2)

4. Warm-Up:

5. Decimals: Objectives
1.
2.
3.
4.
5.
6.
Read decimals
Write decimals
Compare the value of
decimals
+, -, x, / decimals
Round decimals to
nearest tenth
Round decimals to
nearest hundredth

6. Decimals: Definition
 A decimal is a fraction with a denominator that is a
multiple of 10.
 The decimal (.) is used to indicate place value.
Examples:
3
equals 0.3 stated as "three tenths"
10
18
equals 0.18 stated as "eighteen hundredths"
100
Each decimal expression with a value less than 1 is
preceded by a leading zero to emphasize the presence of
a decimal. For example, .7 is correctly written as 0.7

7. Decimals: Definition
 A decimal is a fraction with a denominator
that is a multiple of 10.

8. Decimals: Place values

9. Decimals: Reading
 Reading
1.
2.
Read the decimal point as the word “and”
Read the decimal fraction on the right
Example: 8.3 = “eight and three tenths”
4.06 = “four and six hundredths”
0.5 = “five tenths
The word „point‟ is not a number and is not
used when reading decimals.

10. Decimals: Adding and Subtracting
 Place the numbers in the columns so the decimals
are lined up. Add or subtract from left to right.

Add or Subtract as indicated:
16.4
21.8
+ 3.0
.7
.750
+ .324
.7 00
- .050
Safety Point: Zeros may be added to help line up
decimals – don’t include in final answer!

11. Decimals: Multiplying
 Place decimal correctly!
 Multiply numbers; in the product (answer), count
decimal places right to left equal to the total
decimal places in the numbers being multiplied.
1.2
x 3.2
24
36
384. = 3.84
Find the product:
.7
x .050

12. Decimals: Multiplying (cont‟d)
 Add zeros where needed to ensure correct
placement of decimal in answer
 Example: 0.11 x .33
Find the product:
0.11
x 0.33
33
33
0363. = 0.0363
.12
x .14

13. Multiplying by Decimal Movement
 Multiplying by 10, 100, 1,000 can be done by
moving decimal to the right one space for each
zero in the number by which multiplying
 Example:
1.6 x 10 = 1.6 = 16
5.2 x 100 = 5.20 = 520
.7 • 10 =
.8 • 100 =

14. Decimals: Dividing a Decimal
 To divide by a whole number, place decimal in
quotient directly above decimal in dividend
3.5
5 17.5
- 15
25
- 25
0
Find the quotients:
22.3 ÷ 8
35.7 ÷ 4

15. Decimals: Dividing by a Decimal
 Move the decimal in the divisor to the right until the
number is a whole number. Then move the decimal in
the dividend the same number of spaces.
.
0.3 6.96
23.2
3 69.6
-
6
9
Find the quotient:
12.1 ÷ .8
-
9
6
-6
0

16. Reminders:
*This week‟s class work due today
*Alt. Khan due today, regular Khan Sunday

18. Fractions/Decimals & Percent Unit