Drawing Tens and Ones to Show Your Adding Work to Someone Else

You will meet this idea in ordinary days. Sketching a plan lets a builder show the owner what will happen before any wood is cut. This is worth learning because showing your work is how others can check and learn from your thinking.

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.

Here is today’s math treasure. Draw tens as long sticks and ones as small dots. To show 26 plus 7, draw two sticks and six dots, then seven more dots. Circle ten dots and turn them into a new stick.

Now count: three sticks and three dots, which is 33. A drawing lets someone else follow your thinking without you saying a word, and it lets you see whether your regrouping really happened.

Watch out for forgetting to circle. Drawing thirteen loose dots and calling it thirty one is a common slip. The circle around ten dots is the whole point of the drawing, because it shows the moment the regrouping happened. Take your time. Careful is better than fast.