Chapter 4 NegaTive NuMberS 79
DeMYSTiFieD / algebra DeMYSTiFieD / HuttenMuller / 000-0 / Chapter 4
The difference of 125 and 75 is 50. Because 125 is larger than 75, we use the
sign on –125 for the sum: −+ 125 75 =− 50.
−+= 10 48 ____.
The difference of 48 and 10 is 38. Because 48 is larger than 10, we use the
sign on 48 for the sum: −+= 10 48 38.
PRACTICE
Find the sum.
- −10 + 8 =
- −65 + 40 =
- 13 + (−20) =
- −5 + 9 =
- −24 + 54 =
- −6 + 19 =
- −71 + 11 =
- 40 + (−10) =
- 12 + (−18) =
SOLUTIONS
- −10 + 8 = −2
- −65 + 40 = −25
- 13 + (−20) = −7
- −5 + 9 = 4
- −24 + 54 = 30
- −6 + 19 = 13
- −71 + 11 = −60
- 40 + (−10) = 30
- 12 + (−18) = −6
Subtracting a Larger Number from a Smaller Number
To illustrate the next arithmetic rule, let us consider the temperature being
above 0° and the temperature dropping. If it drops only a little, the temperature
remains above 0°, but if it drops enough, the temperature will be below 0°.
Suppose the temperature is 20°. If it decreases by 10°, then it is still above 0°.
PRACTICE
Find the sum.
SOLUTIONS
- −10 +
