Idea 2of 23Builds onA digit is worth its place
Ten of a place make one of the next
How many of one place make one of the next place?
Today you'll discover
- what one ten thousand can be traded for
- why the count changes but not the amount
- how to trade the other way
Think firstOne counter in the ten thousands column
One ten thousand is traded for thousands. How many thousands do you get?
Decide first, then press Next. Count the counters before and after the trade.
A place-value mat of five columns with one counter in the ten thousands column. The counter is traded: it fades, and ten new counters appear in the thousands column. The counts read 0 and 10, and two lines say 1 × 10 000 = 10 000 and 10 × 1 000 = 10 000. The last step shows 25 counters in the hundreds column.
See the whole ideathe big idea and the key word, in one place
The big idea
Ten of a place make one of the next place left, so one can be traded for ten.
Ten each time
Each place is ten of the place on its right.
- 10 ones1 ten
- 10 tens1 hundred
- 10 hundreds1 thousand
- 10 thousands1 ten thousand
Key word
- trade
- to swap 1 of a place for 10 of the place on its right, or 10 for 1, without changing the amount
Ready to use it?
- Trade 1 of a place for 10 of the next, or 10 for 1.