Question

to subtract 178-135 mentally, carmine adds 5 to each number. karen adds 2 to each number. will both methods work to find the correct answer? why or why not?

Answer 1

Yes

Explanation:

Since the same value, x, is being added to both numbers they are subtracting the answer won't be changed.

178-135=43

183-140=43

180-137=43

Answer 2

Both, the methods will give the correct answer.

Explanation:

We are given the following information in the question:

178 - 135 = 43

If Carmine adds 5 to each number, then,

`(178 + 5) - ( 135 + 5) = 183 - 140 = 43`

If Karen adds 2 to each number than the subtraction problem will look like:

`(178 + 2) - ( 135 + 2) = 180 - 137 = 43`

Adding 5 to each number or adding 2 to each number won't change the answer.

One must make sure that equal amount of quantity should be added to both the components. Sometimes this technique helps us to simplify the problem and it could be solved easily.