What is this skill?
Comparing two-digit numbers means deciding whether one number is greater than, less than or equal to another, and writing the result with the symbols >, < or =. For example, 52 > 47 and 36 < 63. First graders compare numbers from 10 to 99 using their understanding of tens and ones.
The rule is to compare the tens first. The number with more tens is greater, whatever the ones are, because one ten is more than any number of leftover ones. Only when the tens are the same do you compare the ones: 47 and 43 both have 4 tens, and 7 ones is more than 3, so 47 > 43.
Why it matters
Comparing numbers is place value in action. A child who can explain that 52 is greater than 47 because 5 tens is more than 4 tens, even though 2 is less than 7, really understands what the digits mean. Children who compare digit by digit without that understanding often get confused.
This skill leads directly to comparing three-digit numbers in second grade, ordering numbers, rounding and later comparing decimals. The symbols >, < and = also appear throughout math, so becoming comfortable with them early helps.
It also gives children a quick way to check their own work. If a child adds 30 to 45 and gets an answer smaller than 45, comparing the two numbers shows at once that something went wrong. Being able to say which of two numbers is bigger, and by roughly how much, is the start of good estimation.
Common mistakes
- Comparing the ones digits instead of the tens, deciding 29 > 31 because 9 is bigger than 1. Building both numbers with tens and ones shows the truth quickly.
- Mixing up the symbols. A common trick is that the open side faces the bigger number; some children imagine the symbol as a mouth that wants to eat the larger number.
- Treating numbers with the same digits as equal, like 36 and 63. Asking "how many tens does each have?" makes the difference clear.
How to help at home
- Play a card version of "war" with two-digit numbers: each player turns over two cards to make a number, and the larger number wins. Say the comparison out loud, such as "64 is greater than 58."
- Write two numbers and ask your child to put the right symbol between them, then explain why. The explanation is more important than the symbol.
- Compare real numbers: page counts of two books, prices of two items under a dollar, or the numbers of two houses on your street.
- Use dimes and pennies to build both numbers. Whoever has more dimes has more money, unless the dimes are equal.
Worked examples
These are real questions from the Tutorsaurus comparing two-digit numbers practice, with the answers worked out.
Example 1
76 ? 75
Choices: >, <, =
Answer: >. 76 > 75. The tens are the same, so compare the ones.
Example 2
42 ? 18
Choices: >, <, =
Answer: >. 42 > 18. Compare the tens first.
Example 3
87 ? 81
Choices: >, <, =
Answer: >. 87 > 81. The tens are the same, so compare the ones.