The purpose of this activity is to help students learn groupings:
- within 10, for example 3+7=10
- with 5, for example 5+2=7
recall groupings within 10. For example 3 and 7 make 10; 8 and 2 make 10.
The abacus can be used effectively to help develop and reinforce student knowledge of groupings. These include:
- Develop knowledge of groupings within 10 (for example, 2+8=10) by pushing across a small number of beads and asking
How many more to make 10?
- Develop knowledge of groupings with 5 (for example 5+2=7) by pushing across 5 beads and asking
How many more to make 7?
- Develop knowledge of groupings with 5 (for example 5+4=9) by pushing across a small number of beads, for example 9, and ask
How many beads did I just push over?
How do you know it’s 9 without counting the beads? Encourage answers that focus on the groupings such as “I know 5 and 4 is 9” or “I know 9 is 1 less than 10.”
The groupings identified using the abacus can be reinforced using finger patterns.