1Cademy - Subtracting $$3 - 1$$ and $$-3

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Subtracting Integers with the Same Sign

Example

Subtracting $3 - 1$ and $-3 - (-1)$ with Counters

Using the two-color counter model, we can visualize subtracting integers when we already have enough counters of the needed sign to take away directly.

For $3 - 1$ , we start with 3 positive (blue) counters. We take away 1 positive counter, which leaves exactly 2 positive counters. Therefore, $3 - 1 = 2$ .
For $-3 - (-1)$ , we start with 3 negative (red) counters. We take away 1 negative counter, which leaves exactly 2 negative counters. Therefore, $-3 - (-1) = -2$ .

In both cases, because the starting number and the number being subtracted share the same sign, we can complete the subtraction simply by removing the appropriate number of counters.

Updated 2026-05-01

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