2-Digit Subtraction Games for Kids

How to Learn 2-Digit Subtraction

To subtract two-digit numbers, split each number into tens and ones, subtract the tens, subtract the ones, and put the two together. When there are not enough ones, regroup: 1 ten makes 10 ones. Every 2-digit difference hides a one-digit fact, like 12 − 8 inside 52 − 28, so the subtraction facts within 20 need to be quick first.

Tens and ones

Every two-digit number is made of tens and ones: 76 is 7 tens and 6 ones, and 24 is 2 tens and 4 ones. Take tens from tens and ones from ones: 7 tens − 2 tens = 5 tens, or 50, and 6 − 4 = 2. Together, 76 − 24 = 52. Base-ten blocks make this easy to see: a rod is a ten, and a cube is a one.

Subtract the tens

Subtracting tens is like subtracting ones, only with tens: 7 tens − 3 tens = 4 tens, so 70 − 30 = 40. Taking 10 from a 2-digit number changes only its tens digit: 10 less than 56 is 46, and 56 − 20 = 36. On the hundred chart below, every −10 is one row up. Finding 10 less in their head, without counting, is a 1st grade goal.

Subtract a one-digit number

In 48 − 3, the tens stay and only the ones change: 8 − 3 = 5, so 45. When there are not enough ones, the answer moves into the previous ten. For 43 − 5, break a ten: 13 − 5 = 8, and the tens go from 4 to 3, so 38. It is the same fact your child uses for 13 − 5 = 8.

Regrouping, step by step: 52 − 28

Regrouping, also called borrowing, is needed when the ones you have are fewer than the ones you take away. Here is 52 − 28 the way it is written in columns:

1. Look at the ones: 2 is smaller than 8, so regroup. Break 1 ten into 10 ones. 5 tens and 2 ones become 4 tens and 12 ones.
2. Subtract the ones: 12 − 8 = 4. Write 4 in the ones place.
3. Subtract the tens, after the broken ten is gone: 4 − 2 = 2 tens.
4. 2 tens and 4 ones make 24, so 52 − 28 = 24.

Check by adding the answer back to the number you took away: 24 + 28 = 52. If the sum is the number you started with, the subtraction is right. The same check works without regrouping: 52 + 24 = 76 confirms 76 − 24.

Common mistakes

• 36 for 52 − 28. Your child took the smaller digit from the bigger one in each place: 5 − 2 = 3 and 8 − 2 = 6, and wrote 36. The ones were swapped instead of regrouped. 2 cannot take away 8 until a ten is broken.
• 34 for 52 − 28. Your child did regroup the ones, 12 − 8 = 4, but left the tens at 5, so 5 − 2 = 3. The ten that was broken has to come off the tens. Adding back catches it: 34 + 28 = 62, not 52.

The online games on this page put both slips among the answers: for 52 − 28, your child sees 36 and 34 next to 24 and learns to tell them apart.

Wondering why your child's homework splits numbers into tens and ones? See expanded form in our guide to new math. The matching addition, including how a new ten is made, is on the 2-digit addition games.

What Grade Learns 2-Digit Subtraction?

Two-digit subtraction starts in 1st grade in the US and becomes fluent in 2nd grade, usually at ages 6-8. Common Core standard 1.NBT.C.6 asks 1st graders to subtract multiples of 10, such as 70 − 30, using place value or the relationship with addition. Standard 2.NBT.B.5 asks 2nd graders to add and subtract within 100 fluently, including a two-digit number minus a one-digit number and two two-digit numbers, with and without regrouping.

In England, Year 2 children subtract a two-digit number and ones, a two-digit number and tens, and two two-digit numbers. In Year 3 they move on to column subtraction, including exchanging.

Age

6-8

US grade

Grades 1-2

Standard

Common Core 1.NBT.C.6, 2.NBT.B.5

England

Years 2-3