Use counters to subtract –4 − –1.

You start with:

You subtract:

Which picture shows the difference?

You are trying to calculate -4 − (-1).

Start out with 4 negative counters, which represent -4:

Now take away 1 negative counter:

3 negative counters remain. So -4 − -1 = -3.

Use counters to subtract 2 − 2.

You start with:

Which picture shows the difference?

You are trying to calculate 2 − 2.

Start out with 2 positive counters, which represent 2:

Now take away 2 positive counters:

0 counters remain. So 2 − 2 = 0.

Use counters to subtract -4 − -1.

You start with:

Which picture shows the difference?

You are trying to calculate -4 − -1.

Start out with 4 negative counters, which represent -4:

Now take away 1 negative counter:

3 negative counters remain. So –4 − –1 = –3.