1. 1-7: Adding and Subtracting Integers
Grade 6 Math

2. Why need Integers? Used in everyday situations
Profits +ve and losses –ve
Rise in prices and fall in prices
Height above sea level, depth below sea level
Direction (E is +ve, W is –ve, N is +ve, S is –ve)
Rise and fall in temperature

3. Rules to add Adding Integers Same sign Different sign
First find absolute value of each number
Then subtract the numbers
Sum has the sign of the integer with greater absolute value
Sum of 2 positive integers is positive
Sum of 2 negative integers is negative

4. Rules to subtract Subtracting Integers
To subtract integers, add the opposite
Then following the rules for adding integers
Example: 6-(-3) = = 9

5. Properties of addition
Sum of any 2 integers is always an integer
Property
Addition
Commutative
a + b = b + a
Associative
(a + b) + c = a + (b + c)
Identity
a + 0 = a, 0 + a = a
Inverse
a + (-a) = 0
Two numbers whose sum is zero are called additive inverses.

6. REMEMBER Negative numbers < 0 < positive numbers
Greater the number lesser is its opposite
Lesser the number greater is its opposite

7. Homework
1-6: p : # 19 – 47 o
1-7: p # 9, 11, o