What is this skill?
Comparing groups means deciding which of two collections has more objects, which has fewer, or whether they have the same number. Kindergartners work with groups of up to 10. There are two good ways to do it: count both groups and compare the numbers, or match the objects one to one and see which group has some left over.
The words matter here. "More," "fewer," "less," "same," "equal" and "greater" are math vocabulary, and many children understand "more" well before "fewer." Practicing both directions, which has more and which has fewer, makes sure your child understands the comparison rather than always picking the bigger group.
Why it matters
Comparing quantities is the start of understanding that numbers have size and order. Knowing that 8 is more than 5 because a group of 8 has more things than a group of 5 is the foundation for comparing two-digit numbers in first grade, three-digit numbers in second grade, and fractions and decimals later on.
Comparison is also where subtraction starts to make sense as "how many more?" A child who can line up 7 red blocks against 4 blue ones and see 3 extra red blocks is already thinking about the difference between two numbers.
Common mistakes
- Judging by how much space a group takes up instead of how many objects it has. Five large toys spread out can look like "more" than eight small beads bunched together. Counting or matching settles it.
- Always choosing the bigger group, even when the question asks which has fewer. Read the question together and stress the word: "Which has fewer?"
- Counting both groups correctly but not knowing which number is bigger. Placing the numbers on a number line, or recalling that bigger numbers come later when we count, helps connect the two.
How to help at home
- Make two piles of snacks and ask which has more. Then let your child check by lining them up side by side, one under the other, so the extra ones stand out.
- Use "fewer" as often as "more": "Who has fewer grapes, you or me?" Hearing the word in real situations is the quickest way to learn it.
- Ask "how many more?" occasionally. If you have 6 crackers and your child has 4, how many more do you have? Matching the crackers in pairs shows the answer is 2.
- Try trick setups: spread out a small group and bunch up a larger one, and see whether your child counts before answering.
Worked examples
These are real questions from the Tutorsaurus comparing groups practice, with the answers worked out.
Example 1
Which group has fewer?
Choices: 3, 1
Answer: 1. 3 is more than 1. The group with 1 has fewer.
Example 2
Which group has fewer?
Choices: 1, 5
Answer: 1. 5 is more than 1. The group with 1 has fewer.
Example 3
Which group has fewer?
Choices: 7, 9
Answer: 7. 9 is more than 7. The group with 7 has fewer.