1-7 Adding and Subtracting IntegersMiss Tilton

1-7 Adding Integers Adding zero does not change an

integer: Zero property

Examples: – 12 + 0 = – 12 0 + (– 88) = – 88

1-7 Adding Integers Adding integers with the same sign:

Find the sum Keep the sign

Find the sum of – 5 + – 2

1-7 Adding Integers Examples of addition with the same

sign: 1. 3 + 5 = 82. – 3 + (– 5) = – 83. – 50 + – 102 + – 5 = – 157

Try these…– 1 + (– 23) = – 5 + (– 2) + (– 7) =

– 24 – 14

1-7 Adding Integers Adding integers with different

signs: Find the difference (of the absolute

values) Use the sign of the number with the larger

absolute value Find the sum of – 4 + 5

1-7 Adding Integers Find the sum of 5 + (- 4)

1-7 Adding Integers Examples of addition with different

signs: 1. 9 + – 6 = 32. – 34 + 5 = – 293. – 49 + 54 + – 14 = – 14

Try these…2 + (– 10) = 30 + – 5 21 + (– 39) =

– 8 25 – 18

1-7 Adding Integers If you have no money on Monday. Your

mom lets you borrow $ 8 on Tuesday, and you pay her back from the $ 10 you earn on Wednesday, how much money do you have?

1-7 Subtracting Integers Subtracting a positive using a

number line: Find the first value on the number line Move to the LEFT (2nd number)

Find the difference: 3 – 7 Find 3 on the number line Move – 7 (or 7 spaces to the LEFT)

3 – 7 = – 4

1-7 Subtracting Integers Find the difference: – 3 – 1

Find – 3 on the number line Move – 1 (or 1 spaces to the LEFT)

– 3 – 1 = – 4 Try these…

2 – 4 = – 3 – 5 12 – 19 – 6 – 8 – 7

1-7 Subtracting Integers Subtracting a negative using a

number line: KEEP THE FIRST INTEGER THE SAME!!! ( + or

– ) Change – – to +, because taking away a

negative is adding Follow the rules for addition

Find the difference: 3 – (– 6) Change 3 – (– 6) to 3 + 6 Add

3 + 6 = 9

1- 7 Subtracting Integers Try these…

2 – (– 4) = 3 – (– 5)= 12 – (– 9)=2 + 4 = 3 + 5 = 12 + 9 = 6 8 21

1-7 Subtracting Integers Find the difference: – 4 – (– 5)

Change – 4 – (– 5) to – 4 + 5 Add – 4 + 5

– 4 + 5 = 1

1-7 Subtracting Integers Try these…– 2 – (– 4) = – 3 – (– 3)= – 12 – (– 9)=

– 2 + 4 = – 3 + 3 = – 12 + 9 = 2 0 – 3