Interesting Integers!Let’s subtract.
What You Will Learn Rules for subtracting Method for subtracting
Are you ready??
We will use algebra tiles to solve some subtraction problems
Remember zero pairs – 1 set of opposite colors will be a zero pair
Red is positive
Yellow is negative
1 yellow + 1 red = 0
Let’s try a problem
-2 - 4 =
This is our zero pair bank
Problem: 4 - 2
-2 - 4 =
Remove 4 red (positive)
Problem: 5 - -2
Problem: -3 - -4 =
Subtracting Integers
To subtract integers, add its opposite!2 – 7
2 + (-7)
Follow the add rules
Here are some examples
5 – (+5)
5+ (-5) = 0
5 – (+10)
5 + (-10) = -5
Integer Subtraction RuleSubtracting a negative number is the same as adding a positive. Change the signs and add.
2 – (-7) is the same as
2 + (+7)
2 + 7 = 9!
Here are some more examples.
12 – (-8)
12 + (+8)
12 + 8 = 20
-3 – (-11)
-3 + (+11)
-3 + 11 = 8
2 – (+7)=
4 – (-5) =
-10 – (-6) =
-21 – (+63) =
7-2=5
4 +5 = 9-10 + 6 = -4
63 – 21 = 42
Forget the sign, find the difference, use the sign of the larger
Forget the sign, find the difference, use the sign of the larger
Try these
1. 8 – (-12) =
2. 22 – (-30) =
3. – 17 – (-3) =
4. –52 – 5 =
8 – (-12) = 8 + 12 = 20
2. 22 – (-30) = 22 + 30 = 52
3. – 17 – (-3) = -17 + 3 = -14
4. –52 – 5 = -52 + (-5) = -57
Homework – page 268/269
16 through 28 all
FormativeOrder least to greatest
-10 0 8 -14 22 -1.2 1.3
Solve
-15 + 8 =
-4 - -4 =
5 + -3 =
-4 - +6 =
HomeworkBased on formative results-from textbookOrdering and comparing – pg 24 #1, #2Adding pg 27 #5, #6, #7, #8Subtracting pg 28 #1 #2 #3 #4