Let’s do these subtraction problems by imagining we are crossing off “buns.” We always start by taking buns away from the emptier tin, and then see how many more buns we need to cross off from the full tin. I’ll do the first one for you!

Let’s Play: In the picture, we can see what 17 buns looks like—we have 10 buns in the full tin, and 7 buns in the other tin. And now we have to get rid of 9 buns to figure out 17 – 9! Hmm, first we’ll take away the 7 buns from the emptier tin—the one on the right. But to take off a total of 9, we still have to cross off 2 more buns from the full tin, right? Here’s the picture we can imagine:

Or we can use our fingers to cover up those buns! And how many buns are left? We don’t have to even count—since we took 2 buns away from 10, we know there must be 8 buns left over, since 10 – 2 = 8.

Great! We’ve just done the problem: 17 – 9 = 8. Done!

Answer: 8 buns

Practicing with ten frames (tins!) makes it easier for us to “see” addition and subtraction problems in our minds. Keep it up, and soon you’ll be adding and subtracting like a champ!

(Answers on page 148.)