When you can count past nine, something clever happens: we group ten ones together to make one ten. After that, a two-digit number is just some tens and some ones.

Take 23. The 2 is not really "two" — it means two tens, which is twenty. The 3 means three ones. Put them together:

Press play. First ten loose dots bundle up into a single ten. Then we build a number out of a few tens and a few ones — and read it aloud. Replay it: a different number is built each time.

Khan Academy breaks a two-digit number into its tens and ones here: