•Objectives:
•In this lesson,you are expected to:
•1. Use fundamental operations using different
approaches;
•2. Solve word problems involving fundamental
operations of integers.
•Problem: You wantto buy house that costs
Php800,000. You only have Php500,000.
If you buy the house, what will your debt
be?
•If you spend more money than you have,
you go into debt.
Adding Integers
Use anumber line to help visualize the addition of
integers.
5
2 7
3
6 9
4
2 6
9.
Adding Integers
Use anumber line to help visualize the addition of
integers.
3
8 5
3
4 1
10.
ADDING INTEGERS
•We canuse positive and negative counters to model the addition
of integers.
Positive Integer Negative Integer
A positive integer paired with a negative integer form a
zero pair. The value of a zero pair is 0.
Do you noticea pattern or rule?
Adding Integers with like signs.
- When the signs are the same,
add the numbers together and
keep the sign.
16.
WE NOW HAVETHE FOLLOWING
GENERALIZATION:
ADDING A POSITIVE INTEGER TO MEANS
MOVING ALONG THE REAL LINE A DISTANCE OF
UNITS TO THE RIGHT FROM . ADDING A
NEGATIVE INTEGER – TO MEANS MOVING
ALONG THE REAL LINE A DISTANCE OF UNITS
TO THE LEFT FROM.
DID YOU NOTICEA PATTERN OR RULE?
Adding integers with unlike signs.
- When the signs are different, subtract
the integers and keep the sign of the
larger digit.
22.
Adding Integers withlike signs.
- When the signs are the same, add the numbers together
and keep the sign.
-9 + -3 = -12
Adding integers with unlike signs.
- When the signs are different, subtract the integers and
keep the sign of the larger integer.
-9 + 3 = -6
Quick Review ofAdding Integers
• Adding Rule #1
–If the signs are the same, add
as you normally do.
–Keep the same sign.
• 5 + 8 =
• -8 + -17 =
• Adding Rule #2
– If the signs are DIFFERENT,
pretend the signs aren’t there.
– Subtract the smaller from the
larger one.
– Keep the sign of the number with
the GREATEST Absolute Value.
• 19 + -11 =
• 24 + -86 =
13
-25
8
-62
31.
THE HIGHEST POINTIN ASIA IS THE TOP OF
MOUNT EVEREST, AT A HEIGHT OF 29,028
FEET ABOVE SEA LEVEL. THE LOWEST
POINT IS THE DEAD SEA, WHICH 1312 FEET
BELOW SEA LEVEL. HOW MUCH HIGHER IS
MOUNT EVEREST THAN THE DEAD SEA?
32.
3 Steps toSubtract
Integers
• Keep
–Keep the 1st
number
• Change
–Subtraction sign to Addition
• Opposite
–Write down the opposite of the 2nd
number
-Then add the way you normally do.
GROUP ACTIVITY:
MATERIALS: FLASHCARDS/POWER POINT, SHOW-ME-BOARD
MECHANICS:
A.DIVIDE THE CLASS INTO 5 GROUPS.
B.CHOOSE A LEADER
C. TEACHER FLASHES NUMBERS ON THE SLIDES
D.LEADER WILL WRITE THE CORRECT ANSWER ON THE SHOW-ME-BOARD
E.THE FIRST GROUP TO FLASH THE CORRECT ANSWER WILL GET 1 POINT
F.THE TEACHER CHECKS THE ANSWERS.
G.THE GROUP HAVING THE MOST NUMBER OF CORRECT ANSWERS WINS.
(Subtraction of integersmeans adding the minuend and the
opposite of the subtrahend.) or
Subtract Integers
1.Keep
Keep the 1st
number
2.Change
Subtraction sign to Addition
3.Opposite
Write down the opposite of the 2nd
number
-Then add the way you normally do.
Why?
Positive x Positive= POSITIVE
Your bank records 5 deposits of Php300 each.
5(300) = +1500
Positive x Negative = NEGATIVE
Your bank records 5 withdrawals of Php30 each.
5(-300) = -1500
Negative x Positive = NEGATIVE
Your bank loses track of 5 deposits of Php300 each.
-5(300) = -1500
Negative x Negative = POSITIVE
Your bank loses track of 5 withdrawals of Php300 each.
-5(-300) = +1500
58.
Some simple ruleswill help you when multiplying negative numbers.
The rules are the same for division.
•If there is one negative number, then the answer is negative.
•If two numbers are negative, then the answer is positive.
8 x 5 = 40 -8 x 5 = -40
8 x -5 = -40 -8 x -5 = 40
If the signs are the same = positive answer.
If theMultiplication of integers
++ Answer is +
-- Answer is +
+- Answer is -
-+ Answer is -
59.
GROUP ACTIVITY
• Materials:flash cards/power point, show-me-board
• Mechanics:
• a.Divide the class into 5 groups.
• b.Choose a leader
• c. Teacher flashes numbers on the slides
• d.Leader will write the correct answer on the show-me-board
• e.The first group to flash the correct answer will get 1 point
• f.The teacher checks the answers.
• g.The group having the most number of correct answers wins.
HOW DO WEMULTIPLY INTEGERS?
1. IF THE SIGNS ARE THE
SAME THE ANSWER
IS POSITIVE
2. IF THE SIGNS ARE
DIFFERENT
THE ANSWER
IS NEGATIVE
64.
Try it withyour seatmate:
6 x 8 = - 6 x 8 = 6 x -8 = -6 x -8 =
7 x 4 = -7 x 4 = 7 x -4 = -7 x -4 =
|-8 x 3| = |5 x (-2) – 1| =
2 x |3 – 9| =
6 x 8 = 48 - 6 x 8 = -48 6 x -8 = -48 -6 x -8 = 48
7 x 4 = 28 -7 x 4 = -28 7 x -4 = -28 -7 x -4 = 28
|-8 x 3| = 24 |5 x (-2) – 1| = 11 2 x |3 – 9| = 12
Pair-share: Multiply the ff.
Click for answers:
Dividing Integers
Whenever wedivide two integers
with “like” signs, the answer is
always positive.
¿
𝟏𝟔÷𝟒=𝟒
(−)÷(−)=+¿
−𝟏𝟐÷(−𝟒)=𝟑
72.
Dividing Integers
Whenever wedivide two integers
with “unlike” signs, the answer is
always negative.
What did you notice about the rules for
multiplying and dividing integers?
¿
𝟗÷ (−𝟑)=−𝟑
(−) ÷ ¿
If you said they’re exactly the same,
you’re right!
−𝟏𝟓÷𝟑=¿−𝟓
73.
Some simple ruleswill help you when multiplying negative
numbers. The rules are the same for division.
•If there is one negative number, then the answer is
negative.
•If two numbers are negative, then the answer is positive.
40 ÷ 8 = 5
-40 ÷ -8 = 5
-40 ÷ 8 = -5
40 ÷ -8 = -5
If Division of Integers
++ Answer is +
-- Answer is +
+- Answer is -
-+ Answer is -
74.
It’s Time toShow Your
Stuff!
¿−𝟖
divide the following integers.
¿−𝟔
How do wedivide integers?
When we divide two integers, the sign rules are different
than when we add or subtract signed numbers.
When divide two positive integers, the solution is
positive.
12 ÷ 3 = 4
16 ÷ 8 = 2
8 ÷ 8 = 1
77.
How do wedivide integers?
When we divide two negative integers, the
solution is also positive.
(-12) ÷ (-3) = 4
(-16) ÷ (-8) = 2
(-8) ÷ (-8) = 1
78.
How do wedivide integers?
When we divide one positive & one negative integer,
the solution is always negative, regardless of which is
larger or which is written first.
12 ÷ (-3) = - 4
(-16) ÷ 8 = -2
(-8) ÷ 8 = -1