How to compare numbers to 100

In the introduction you saw that 45 is greater than 38. You knew it just by looking at the baskets. Now you'll learn a trick that works for every pair of numbers — even when you don't have any baskets.

A two-digit number has two parts

Every number from 10 to 99 is made of tens and ones.

• The number 47 has 4 tens and 7 ones.
• The number 74 has 7 tens and 4 ones.

You learned that in the "Numbers to 100" topic. We use it here.

The neat trick in two steps

When you compare two two-digit numbers, do this:

1. Look at the tens first. The number with more tens is the bigger one.
2. If the tens are the same, look at the ones. Then the bigger ones digit wins.

That's it. No counting up or down.

Let's look at examples

47 and 74

• Tens: 47 has 4 tens, 74 has 7 tens.
• 7 is more than 4, so 74 > 47.

63 and 68

• Tens: 63 has 6 tens, 68 has 6 tens. The same!
• I move on to the ones: 63 has 3, 68 has 8.
• 8 is more than 3, so 63 < 68.

50 and 50

• The tens and the ones are the same — the number is exactly the same.
• 50 = 50.

The finger trick

When comparing, cover the ones with your finger and look only at the tens. If the tens are different, you have the answer right away. If they're the same, lift your finger and look at the ones too.

Summary

• We look at the tens first — whichever has more is bigger.
• If the tens are equal, the ones decide.
• The finger trick works on paper and in your head.