MA 2.08Golden Bead Subtraction
The child takes a smaller quantity away from a larger one, exchanging down when a category does not have enough, and reads what is left.
Age 5Work 8 of 11 in Decimal System
Presentation
- 1
Form 5,867 with beads and cards in front of the child.
- 2
Show the card set 3,423: 'We are going to take away this much.'
- 3
Starting with the units, the child removes 3 units, then 2 tens, 4 hundreds, and 3 thousands, and places them on a separate tray.
- 4
Count what is left and find the cards: 2,444.
- 5
Read: '5,867 minus 3,423 equals 2,444'. Write it in columns.
- 6
In a later lesson use a problem where a category is short, such as 5,832 − 1,617. When there are not enough units, exchange one ten for ten units, then take away.
Extensions, easiest to hardest
- Exchanging in two categories.
- Subtraction with zero in the larger number (4,006 − 1,238).
- Child checks a subtraction by adding the answer and the part taken away.
Control of error
The removed beads and the remaining beads, pushed back together, must rebuild the starting number.
Ready to move on when the child…
- Exchanges down without prompting when a category is short
- Starts from the units
- Reads and records the answer correctly