Download Adding and Subtracting Integers with Double Signs

Adding and Subtracting
Integers
Objectives:
SWBAT add or subtract two integers
and give the answer the correct sign.
SWBAT simplify numbers that have two
signs (double negative signs).
Vocabulary
Integers
whole numbers and their opposites
(not fractions/not decimals)
Sign
a number that is either positive or negative
+ (Sign is not always shown)
Negative -- – (Sign must be shown)
Positive --
Double Sign one number with two signs.
(A number can only have one sign – it is either
positive or negative.)
Adding Integers
Rule: *When signs are the same, you add and keep the
sign.
Pos. + Pos. = Pos.
4 + 5 =
9
10 + 4 =
14
Neg. + Neg. = Neg.
-6 + -2 =
-8
-3 + -12 =
-15
Rule: *When signs are different, you subtract and keep the
sign of the larger number.
Pos. + Neg. = sign of larger #
4 + -6 =
-2
10 + -2 =
Neg. + Pos. = sign of larger #
-2 + 4 =
2
-8 + 1 =
8
-7
Subtracting Integers:
Rules: 1- When signs are the same, you add and keep the
sign.
2- When signs are different, you subtract and keep the
sign of the larger number.
12 – 10 =
-8 – 10 =
11 – 14 =
2
5–5=
-9 – 4 =
2–6=
0
-18
-3
-4
-13
Double Signs:
Rule: Make the double negatives a positive then follow the
adding integer rules.
Keep – Change – Change
4 – (-2) =
4+2=
6
-4 – (-12) =
-4 +12 =
8
-6 – (-2) =
-6 + 2 =
-4
Practice
1. 5 + 2 =
2. -4 + 8 =
4
7
4. 3 – 1 =
3. 5 + -7 =
-2
2
6. -5 – 10 =
5. 4 – 10 =
-15
-6
7. 8 – (-4) =
8+4=
12
8. -7 – (-3) =
-7 + 3 =
-4