Here is a number sense trick to help you calculate subtraction using mental math.

We want to find the difference of 100 – 76. Using our number sense, we turn to “friendly numbers” to calculate *how far apart* are 76 and 100.

Starting at 76, we can first find how far apart are 76 and 80 (the nearest multiple of 10) and get **4**.

Then, we find how far apart are 80 and 100, and get **20**.

So, 76 and 100 are **4 + 20 = 24** apart, and our final answer is

100 – 76 = 24.

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