Read teen numbers as ten and extra ones

What it looks like when your child can do it

• — Shown a packed box and a second box with four beans, your child says ten and four more, fourteen.
• — Your child points to the 1 in 16 and says that is the packed ten.
• — Asked to build thirteen, your child fills one box first, then puts three beans in a second box.

How to teach it at the kitchen table

1. 01

   Set two boxes side by side

   Make two egg carton boxes of ten cups. Fill the left box completely and say ten. The box on the right holds the extras.

2. 02

   Say ten and some more

   Put two beans in the right box. Say ten and two more is twelve. The same pattern holds for every teen: thirteen is ten and three more, all the way to nineteen, ten and nine more.

3. 03

   Read the two marks

   Write 12 on a card. The 1 on the left stands for the packed ten. The 2 on the right stands for the extra ones. Point to each box as you point to each mark.

4. 04

   Say ten without recounting the box

   Your child should say ten for the packed box at once, then count only the extras. Counting every bean from one still lands on the right number, but it skips the packed ten this page is about.

You will need: Two dozen-egg cartons, each cut down to two rows of five cups · Twenty dried beans or buttons · Small counters like beans, buttons and pennies can choke a child, so stay at the table while they are out and put them away from younger children · Paper and a pencil for writing marks

Try it together

1. Try 1

   Fill the left box. Put five beans in the right box. Ask how many beans in all.

   Listen for  Fifteen. Listen for ten and five more first, then fifteen.

2. Try 2

   Show a packed box and six extras. Ask which mark we write.

   Listen for  16. Ten and six more is sixteen, so the 1 on the left stands for the packed box and the 6 on the right for the extras.

3. Try 3

   Write 17 on a card. Ask your child to build it with the two boxes.

   Listen for  One packed box, and seven extras in the second box: its top row full and two more below.

4. Try 4

   Point to the 1 in 19 and ask what it stands for.

   Listen for  The packed box of ten. Some children say one bean, and that is the idea worth working on.

5. Try 5

   Build eighteen. Ask how many holes are empty in the second box.

   Listen for  Two. Eight extras leave two empty holes. This is the stretch question.

Watch for

• — Writing 71 for seventeen, because the word says seven first. Point to the packed box and remind your child its 1 always sits on the left.

If it is not there yet

• — Go back to a single packed box. Fill it quickly and say ten until it never needs counting.
• — Stay with eleven, twelve and thirteen, the three the book names first, building each one several times before moving on to fourteen through nineteen.

A few days of this is normal, and it is time well spent. The lesson will still be there, and it will go faster.

Where this skill comes up

• Zig and Zag Count to Twenty · Lesson 22

  Twenty

  Needs it because twenty is the first number that needs a second full ten, which only makes sense after the teens.