Dynamic Operations in the Decimal System
From wikisori
Contents
Age
4-7
Materials
- Golden bead material
- Large and small numeral cards
- Symbol cards for the operations
- Problem cards for each operation
Preparation
This is an individual presentation.
Presentation
The Change Game:
- A large quantity is placed on the tray and the child is invited to count it.
- Beginning with units, the child counts, but is stopped at 10. Ten units cannot remain loose; they must be exchanged for a ten-bar.
- The ten beads are exchanged for one ten-bar from the bank. The child continues counting units and placing the correct large numeral cards on the tray.
- So on to thousands. The cards are arranged and read.
Addition:
- The directress reads a problem card. The child performs each command as it is read.
Subtraction:
- The directress reads a problem card. The child performs each command as it is read.
- The directress presents the thousand cube and wants to take away 1 unit.
- This may be symbolized with the large and small numeral cards for emphasis. How can this be done? The thousand is changed to 10 hundreds.
- Now can we take away one unit? Not quite yet. Continue on until one unit can be taken away.
- The remaining quantity is counted and represented with small cards.
Multiplication:
- As for addition problem cards are prepared.
Division:
- As with static division the child sets about distributing.
- When he finds that he doesn't have enough for one hierarchy to go around, he must exchange for a lesser hierarchy.
- When there is a remainder, the corresponding small numeral cards are brought and placed after a small card with the initial r to the right of the result.
Control Of Error
The directress.
Points Of Interest
Purpose
- To exchange equal quantities of different hierarchies
- To reinforce the rule: only 9 units can remain loose
- To reinforce knowledge of the composition of each hierarchy (ten tens=100)
- To realize that one unit revolutionizes a large quantity.
- To further understand the concept of addition, subtraction, multiplication, and division
Variation
Links
Handouts/Attachments