Counting Back to Subtract with Numbers Up to 20

This is not just for paper. A driver watching exits count down knows how many are left without any paper. Counting back is everyday thinking. This is worth learning because a strategy that fits the numbers beats a strategy you always use.

Watch for it today, and when you spot it, tell someone what you noticed and how you knew. Ask yourself where else the same idea might be hiding, then go and look. You are going to like this one. Counting back is subtraction without counters. For 14 minus 3, start at fourteen and count back three: thirteen, twelve, eleven.

The answer is eleven. Say the numbers slowly and lift one finger for each step back so you do not go too far. Counting back works beautifully when you are taking away one, two, or three. For larger take aways there are better tricks, which you will learn soon.

Here is a caution. Counting back requires saying the numbers in reverse, which is harder than saying them forward. Practice counting backward from twenty out loud a few times a week. That practice alone will fix most of the mistakes people make with subtraction. Little by little, this becomes something you just know.