number · Year 1 · AC9M1N03
Counting in equal groups
When objects are in equal groups, you do not need to count them one by one. Skip count by the size of a group: say one number for each group. Groups of 2 go 2, 4, 6. Groups of 5 go 5, 10, 15. Groups of 10 go 10, 20, 30. If some are loose, skip count the groups first and then count on the loose ones. To make groups from a collection, skip count until you reach the total and count the numbers you said.
Sample questions
The marbles are in groups of 5. How many marbles are there altogether?
- Each group has 5. Skip count by 5: 5, 10, 15, 20.
- You said 4 numbers because there are 4 groups.
- Check: 5 + 5 + 5 + 5 = 20.
Answer: 20
The marbles are in groups of 2. How many marbles are there altogether?
- Each group has 2. Skip count by 2: 2, 4, 6, 8.
- You said 4 numbers because there are 4 groups.
- Check: 2 + 2 + 2 + 2 = 8.
Answer: 8
The marbles are in groups of 5. How many marbles are there altogether?
- Each group has 5. Skip count by 5: 5, 10, 15, 20, 25.
- You said 5 numbers because there are 5 groups.
- Check: 5 + 5 + 5 + 5 + 5 = 25.
Answer: 25