Written by pHqghUmeSeptember 9, 2025
Abacus Math Program – Lesson 14 – Reverse Double Five
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In Lesson 13 we explored the Forward Double Fives in the forward direction for addition. Now let’s take a look at the double fives in the reverse direction for subtraction. We will use the exact same technique but this time we will perform the 10 pair subtraction rule using two 5 pair movements. Let’s work through some