7th Grade Math · Unit 2
Read what a negative number means, then add or subtract in a short situation.
What the sign says
A negative number is below zero.
Depth, an overdrawn account, and a drop in temperature are common meanings.
A fall is subtraction
Going down, withdrawing, or getting colder is subtraction.
Start − the drop, or start + a negative change.
A rise is addition
Going up, depositing, or getting warmer is addition.
Add the change to the starting value, even when the start is negative.
More than one change
Use the changes from left to right.
Rewrite each subtraction as adding the opposite when that makes the signs clearer.
Say what the negative means, or choose the expression.
A negative temperature is below 0.
−5 means 5 degrees below 0°C.
Answer: 5 degrees below 0°C
A negative temperature is below 0.
−8 means 8 degrees below 0°F.
Answer: 8 degrees below 0°F
Depth below the surface is negative.
−15 means 15 meters below the surface.
Answer: 15 meters below the surface
A negative balance is below zero.
The account is overdrawn by 60 dollars.
Answer: The account is overdrawn by 60 dollars.
A negative yardage is a loss.
The play lost 3 yards.
Answer: A loss of 3 yards
A negative elevation is below sea level.
−40 means 40 feet below sea level.
Answer: 40 feet below sea level
A fall is subtraction.
Start at 11, then subtract 4.
11 − 4
Answer: 11 − 4
Going down is subtraction.
30 − 12
Answer: 30 − 12
The fish starts below the surface and goes farther down.
−6 − 2
Answer: −6 − 2
A deposit is addition.
−18 + 25
Answer: −18 + 25
A rise is addition.
−2 + 9
Answer: −2 + 9
One change. Give the new amount with the unit.
A rise is addition.
New value = −9 + 4
−9 + 4 = −5
The result is −5 meters.
Answer: −5 meters
A drop is subtraction.
New value = 7 − 12
7 − 12 = −5
The result is −5 °F.
Answer: −5 °F
A drop is subtraction.
New value = 20 − 35
20 − 35 = −15
The result is −15 feet.
Answer: −15 feet
A rise is addition.
New value = −40 + 15
−40 + 15 = −25
The result is −25 dollars.
Answer: −25 dollars
A rise is addition.
New value = −80 + 30
−80 + 30 = −50
The result is −50 meters.
Answer: −50 meters
A drop is subtraction.
New value = −3 − 6
−3 − 6 = −9
The result is −9 °C.
Answer: −9 °C
A rise is addition.
New value = −12 + 12
−12 + 12 = 0
The result is 0 dollars.
Answer: 0 dollars
A rise is addition.
New value = −8 + 14
−8 + 14 = 6
The result is 6 meters.
Answer: 6 meters
A drop is subtraction.
New value = 10 − 6
10 − 6 = 4
The result is 4 points.
Answer: 4 points
A drop is subtraction.
New value = −25 − 10
−25 − 10 = −35
The result is −35 meters.
Answer: −35 meters
A rise is addition.
New value = −14 + 5
−14 + 5 = −9
The result is −9 °F.
Answer: −9 °F
Two changes, in order.
Apply the changes from left to right.
−2 + 8 = 6
6 − 3 = 3
The result is 3 °F.
Answer: 3 °F
Apply the changes from left to right.
−4 + 9 = 5
5 − 6 = −1
The result is −1 °F.
Answer: −1 °F
Apply the changes from left to right.
−30 + 50 = 20
20 − 12 = 8
The result is 8 dollars.
Answer: 8 dollars
Apply the changes from left to right.
−10 − 8 = −18
−18 + 5 = −13
The result is −13 meters.
Answer: −13 meters
Apply the changes from left to right.
15 − 20 = −5
−5 + 3 = −2
The result is −2 feet.
Answer: −2 feet
Apply the changes from left to right.
2 − 7 = −5
−5 − 4 = −9
The result is −9 °C.
Answer: −9 °C
Apply the changes from left to right.
8 − 20 = −12
−12 + 5 = −7
The result is −7 dollars.
Answer: −7 dollars
Apply the changes from left to right.
−50 + 18 = −32
−32 − 7 = −39
The result is −39 meters.
Answer: −39 meters
Apply the changes from left to right.
−6 + 11 = 5
5 + 4 = 9
The result is 9 meters.
Answer: 9 meters
Apply the changes from left to right.
−8 + 3 = −5
−5 − 10 = −15
The result is −15 °F.
Answer: −15 °F
Apply the changes from left to right.
−15 + 40 = 25
25 − 9 = 16
The result is 16 dollars.
Answer: 16 dollars
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