Ten Partners: Learning Every Pair of Numbers That Makes Ten

This idea walks around your house all day. Fingers come in tens. Coins group into tens. Even the Ten Commandments came as a set of ten, a whole and complete number. This is worth learning because ten partners are the backbone of mental math for years to come.

Watch for it today, and when you spot it, tell someone what you noticed and how you knew. This idea is simple once you see it. Two numbers that add up to ten are called ten partners. Here they all are: zero and ten, one and nine, two and eight, three and seven, four and six, five and five.

Say them aloud until they sound like a song. Knowing these by heart is one of the most useful things a first grade mathematician can carry, because ten is the number our whole counting system is built around. Try practicing these as a game.

Someone says a number under ten and you say its partner as fast as you can. Five and five, two and eight, one and nine. Speed here is not showing off. It frees your mind to think about the harder part of a problem. Try a few on your own, and be patient with yourself.