1. Objective: Students will learn how to subtract integers.
October 5, Math 102
Objective: Students will learn how to subtract integers.
Aim: How does adding the opposite mean the same as subtraction, and how does finding the absolute value of numbers help us when adding and subtracting integers?
NYS Mathematics Standards: 7.N.12
Prior Knowledge: Find each opposite:
+7____ ____ _____
Which number has the greater absolute value?
-4 or 1____ or -16____ 9 or -9_____

2. Mini-lesson:
The first step in subtracting integers is to rewrite the subtraction expression as an addition expression.
2 – 5 can be written as the addition expression 2 + (-5)
When we ADD a negative, we go to the LEFT
2 - 5 = -3 is the same as 2 + (-5) = -3

3. Group Practice: (Mr. Brooks will hand out red and yellow counters)
Find the difference of 2 and 5. Use counters.
Write the subtraction expression 2 – 5.
To subtract integers, add the opposite. Write the addition expression 2 + (-5). This is the new expression.
Use 2 positive (yellow) counters to represent the first number.
Use 5 negative (red) counters to represent the second number.
You can make 2 zero pairs (1 red and 1 yellow cancel each other out).
There are 3 negative counters left.
Write the difference (-5) = -3

4. Independent Practice:
Guided Practice:
State which of the following are correct or are not correct and explain why they are wrong:
-12 – (-2) = -10 ____________
The difference of -17 and 6 is -11 ________
|-11| has a greater absolute value than |5| ___________________
Independent Practice:
Complete Exercises 13, 16, 20, 21, 24 and 28
Homework: “Homework Practice” worksheet on integer subtraction