MA 2.05Change Game (Exchanging)
The child counts a large pile of beads in each category and exchanges every ten for one of the next category, learning that no place can hold more than nine.
Presentation
- 1
Place on the rug 17 units, 13 tens, and 4 hundreds in loose piles.
- 2
Start with the units. Count them into rows; at ten, stop: 'Ten units. We can change them for one ten.'
- 3
Carry the ten units to the bank on the tray, exchange them for one ten bar, and place it with the tens.
- 4
Count the units left: 7. Place the card 7.
- 5
Count the tens, now 14. Exchange ten tens for one hundred; 4 tens remain. Place the card 40.
- 6
Count the hundreds, now 5. Place the card 500.
- 7
Stack the cards and read the number: 547.
- 8
State the rule: 'When we have ten of one kind, we change them for one of the next kind.'
Extensions, easiest to hardest
- Include thousands in the pile.
- Exchange the other way: one ten for ten units, one hundred for ten tens.
- Child records the number formed on paper.
Control of error
Ten units laid beside a ten bar must match its length before exchanging; the bank gives one of the next category only for exactly ten.
Ready to move on when the child…
- Exchanges without a reminder whenever a category reaches ten
- Exchanges both up and down
- Reads the final number correctly