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16 votes
Put the same number in each box to make the

calculation correct.
140 + 10 - ___ = _____ - 30

User Ffttyy
by
8.2k points

2 Answers

6 votes

Answer: 90

Explanation:

Let's use x as a placeholder to the number we are trying to find


140+10-x=x-30

Now we need to isolate x

Step 1) Simplify both sides


140+10-x=x-30\\150-x=x-30

Step 2) Add 30 to both sides


150-x+30=x-30+30\\180-x=x

Step 3) Add x to both sides


180-x+x=x+x\\180=2x

Step 4) Divide both sides by 2


(180)/(2)=(2x)/(2) \\90=x

Step 5) Sub our value into the original equation and solve


140+10-x=x-30\\140+10-90=90-30\\150-90=60\\60=60

5 votes

Answer:

The number would be 90

Explanation:

140 + 10 - 90 = 60

90 - 30 = 60

60 = 60

User Sandeep Purohit
by
8.1k points

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