Question

Ethan used compensation to find the sum of 27 + 38. What number is missing from his work?​

Answer 1

See explanation

Explanation:

Given

`27 + 38`

Required

What number is missing in the workings?

The steps is not given. So, I'll solve from scratch

Using compensation to add numbers, we add an imaginary number to one of the number being added.

The aim of this imaginary number is to round up the digit to a multiple of 10.

So:

`27 + 38` becomes

`27 + (38 + 2)`

In this case the added number is (2) ... Note that this (2) will be subtracted after the addition has been completed

`27 + (38 + 2)` =
`27 + 40`

`27 + (38 + 2) = 67`

Subtract the added (2)

`67 - 2 = 65`

Hence:

`27 + 38 = 65`

So, the missing number in Ethan's workings could have been 2