Example

Multiplying 535 \cdot 3, 5(3)-5(3), 5(3)5(-3), and (5)(3)(-5)(-3) with Counters

The two-color counter model effectively demonstrates integer multiplication by interpreting it as repeated addition or subtraction. For 535 \cdot 3, adding 55 positive counters three times gives 1515 positives. For 5(3)-5(3), adding 55 negative counters three times gives 1515 negatives. Conversely, multiplying by a negative number designates taking away. To model 5(3)5(-3), we must subtract 55 positive counters three times. Starting from a blank workspace, we insert 1515 neutral pairs, then remove the 1515 positive counters, leaving 1515 negatives (yielding 15-15). Similarly, for (5)(3)(-5)(-3), we must take away 5-5 negative counters three times. After introducing 1515 neutral pairs, removing the 1515 negative counters leaves 1515 positive counters (yielding 1515). This illustrates why taking away a negative quantity mirrors adding a positive value.

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Updated 2026-04-21

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