ADDING INTEGERS SAME SIGNS SAME signs keep the

ADDING INTEGERS (SAME SIGNS) SAME signs keep the sign 4 + 2 4 positives ADD and = + 2 positives 6 = 6 positives

ADDING INTEGERS (SAME SIGNS) SAME signs the sign -4 add and keep + - 2 4 negatives + = -6 2 negatives = 6 negatives

ADDITION RULES To add two numbers with the same sign, add the numbers together. The answer will have the same sign as the numbers. ex. ) 3 + 5 = 8 -3 + (-5) = -8

SIGNS FOR ADDITION (+) + (+) = + (-) = (+) + (-) = (-) + (+) = Subtract the digits and keep the sign of the larger digit.

Additional Example 1: Using a Number Line to Add Integers Use a number line to find the sum. – 3 + (– 6) – 6 -3 – 9 – 8 – 7 – 6 – 5 – 4 – 3 – 2 – 1 0 You finish at – 9, so – 3 + (– 6) = – 9. 1 2

Additional Example: Using Absolute Value to Add Integers Add. C. (– 2) + (– 4) – 6 Think: Find the sum of – 2 and – 4. Same sign; use the sign of the integers.

Add. C. (– 6) + (– 7) – 13 Think: Find the sum of – 6 and – 7. Same sign; use the sign of the integers.

Additional Example : Application Meka opened a new bank account. Find her account balance after the first four transactions listed below. Deposits: $200, $20 Withdrawals: $166, $38 200 + 20 + (– 166) + (– 38) (200 + 20) + (– 166 + – 38) 220 + (– 204) Use a positive sign for deposits and a negative sign for withdrawals. Group integers with same signs. Add integers within each group. 220 > 204; use the sign of 220. Meka’s account balance after the first four transactions is $16. 16

Check It Out: Example 4 Michael opened a new bank account. Find his account balance after the first four transactions listed below. Deposits: $175, $95 Withdrawals: $133, $65 175 + 95 + (– 133) + (– 65) (175 + 95) + (– 133 + – 65) 270 + (– 198) 72 Use a positive sign for deposits and a negative sign for withdrawals. Group integers with same signs. Add integers within each group. 270 > 198; use the sign of 270. Michael’s account balance after the first four transactions is $72.

Additional Example 2 A: Adding Integers Using Absolute Values Find each sum. – 4 + (– 9) The signs are the same. Find the sum of the absolute values. – 4 + (– 9) Think: 4 + 9. – 13 Use the sign of the two integers.

-42 + (-87) + (-29) = -158 -57 + (-75) + (-38) = -170 The store had more red apples left over. The store started with the same number of red apples and green apples. It sold more green apples than red apples, so it had more red apples left.

-2 + (-3) + (-13) = -18 The hotel guest got off on the 14 th floor. The manager started on the 19 th floor and rode 2 floors down to the 17 th floor when the hotel guest got on. They rode the elevator down 3 floors. 17 − 3 = 14, so the hotel guest got off on the 14 th floor

Questions?

Homework: Complete worksheet front and back. Notes posted on the website.