1-7 Adding and Subtracting Integers Miss Tilton
1-7 Adding Integers zero Adding zero does not change an integer : Zero property Examples: – = – 12 0 + (– 88) = – 88
1-7 Adding Integers same sign Adding integers with the same sign : Find the sum Keep the sign Find the sum of – 5 + – 2
1-7 Adding Integers same sign Examples of addition with the same sign : = 8 2. – 3 + (– 5) = – 8 3. – 50 + – – 5 = – 157 Try these… – 1 + (– 23) = – 5 + (– 2) + (– 7) = – 24 – 14
1-7 Adding Integers different signs 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 different signs Examples of addition with different signs : – 6 = 3 2. – = – – – 14 = – 14 Try these… 2 + (– 10) = 30 + – (– 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 positive : Subtracting a positive using a number line : Find the first value on the number line Move to the LEFT (2 nd 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 negative : 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 Add = 9
1- 7 Subtracting Integers Try these… 2 – (– 4) = 3 – (– 5)= 12 – (– 9)= = = =
1-7 Subtracting Integers Find the difference: – 4 – (– 5) Change – 4 – (– 5) to – Add – – = 1
1-7 Subtracting Integers Try these… – 2 – (– 4) = – 3 – (– 3)= – 12 – (– 9)= – = – = – = 2 0 – 3