Question

Sam wanted to find the difference 10 -(-6).

He said he would add the opposite. This is what he did:

10 - (-6) = 10 + (-6) = 4

Was Sam's thinking correct? Explain. In your explanation, describe how to add the

opposite and use a number line to find the value of 10 -(-6).

Answer 1

Given:

The expression is
`10 - (-6)`.

Sam's calculation is
`10 - (-6) = 10 + (-6) = 4`

To find:

Whether Sam's thinking correct or not.

Solution:

We have,

`10 - (-6) = 10+6`
`[\because (-)(-)=(+)]`

`10 - (-6) = 16`

`10 - (-6) \\eq 4`

Therefore, Sam's thinking was incorrect.

On number first we have to move 10 units from 0 in positive direction after that negative sign means move in left direction.

But we have 2 negative signs so we need to move 6 units more on positive or right direct as shown below.