Operations with integers
- 2. What are Integers? • Integers include all of the positive and negative whole numbers, and zero. Integers NOT Integers 3 -1.652 -4 ¾ 12 2.5 0 0.7
- 3. Adding Integers • On a number line: 1. Find the first number. 2. Move the distance of the second number. a) Positive (+) numbers, move RIGHT b) Negative (-) numbers, move LEFT 3. Where you land is the answer! Example: 5 + 8
- 4. Examples: • -4 + 1 = • 7 + -9 = • -8 + -4 =
- 5. Adding Integers Rules • Use if you don’t have a number line. • When the integers are: ▫ Both Positive: add the numbers Ex: 4 + 6 = ▫ Both Negative: add the numbers and make it negative Ex: -2 + -5 = ▫ One Positive and One Negative: Subtract and use the sign of the bigger number. Ex: -7 + 4 =
- 6. You Try! • Add the integers. • 12 + -4 = • -8 + -9 = • 2 + 13 = • -11 + 5 =
- 7. Subtracting Integers 1/31/13 • Change the minus to a plus, and change the sign of the number you are subtracting. • Then add! • Ex: -14 – 6 = • Subtracting a Negative is the same as Adding! • Ex: 12 – (-3) =
- 8. You Try! • Subtract the integers. • 17 – 4 = • -8 – (-5) = • 2 – 11 = • -4 – 12 =
- 9. Multiplying Integers 2/1/13 • Sign Rules: • Same signs -> Positive answer! + ∙ + = + and – ∙ – = + • Ex: 2 ∙ 3 = 6 and -2 ∙ -3 = 6 • Different signs -> Negative answer! + ∙ – = – and – ∙ + = – • Ex: 2 ∙ -3 = -6 and -2 ∙ 3 = -6
- 10. Examples: • (5)(-12) = • -14 x -8 = • -23 ∙ 7 =
- 11. You Try! • -9 x 17 = • (-20)(-16) = • 14 ∙ -5 =
- 12. Dividing Integers • Sign rules are the same as multiplying! • Examples: • -16 ÷ -8 = • =
- 13. You Try! • -90 ÷ 6 = • • -57 ÷ 19 =