ADDING AND SUBTRACTING INTEGERS NO CALCULATORS Integers are

ADDING AND SUBTRACTING INTEGERS NO CALCULATORS!!!!!!!

Integers are the whole numbers and their opposites (no decimal values!) Example: -3 is an integer Example: 4 is an integer Example: 7. 3 is not an integer

How do we add integers When adding integers, always find the sign of the answer first. Any number with no sign is positive. The sum of two negatives is a negative Ex: -9 + -7 -9 – 7 -16 TRY THIS: -3 + -4 -3 – 4 - 7

How do we add integers When adding a negative and a positive, the sign of the answer is the same as the integer farthest from zero. -10 + 7 …. . Which one is farthest from the # 0? -10 …. . So your answer is going to be a negative number! Try this: -13 + 15…. Which one is farthest from the # 0? 15…. So your answer is going to be negative or positive? POSITIVE -- - 13 +15 = 2 To get the answer, subtract. SO what is -10 + 7? 10 -7 = 3…. My answer is going to be negative so the answer is -3!

How do we subtract integers? • • Subtraction and addition are friends, so subtraction just changes itself to addition by changing the second number’s sign. Make sure you follow the addition rules after that. • Example: -4 – 6 means -4 + -6 = -10 • TRY THIS: - 5 – 8 • -5 + - 8 …. WILL YOUR ANSWER BE POSITIVE OR NEGATIVE? • NEGATIVE , because same signs • 5 + 8 = 13 so – 5 – 8 = - 13 Don’t let double negative signs confuse you. • Example: 9 - -12 9 + 12 • TRY THIS: 2 - - 7 • 2+7=9

REVIEW 1. 2. 3. 4. 5. 6. 7. PRACTICE -7 + - 5 = -7 + 9 = -6 + 4 + -5 = 15 + -8 + 12 + 6= 15 – 27 = -3 - -8 = -16 – 19 = 1. 2. 3. 4. 5. 6. 7. PRACTICE -7 – 5 = -12 -7 + 9 = +2 -6 + 4 + -5 = -11 + 4 = -7 15 + -8 + 12 + -6 =-14 + 27 =13 15 – 27 = -12 -3 - -8 = -3 + 8 = 5 -16 – 19 = - 35

HOMEWORK WORKSHEET 1 -1 # 1 - 8 WORKSHEET 1 -2 # 1 -9 DUE MONDAY! Be sure to show all your work, including when you change signs.