How to Teach Subtraction With Borrowing So It Finally Clicks

Quick answer

To teach subtraction with borrowing, show your child these four steps: (1) Start with the ones column. If the top digit is smaller than the bottom digit, (2) borrow 1 ten from the tens column (cross out the tens digit and write one less, then add 10 to the ones). (3) Subtract each column, ones first, then tens. (4) Check by adding the answer and the bottom number to see if you get the top number back. Most kids learn this in 2nd grade.

Subtraction with borrowing is the step that makes a lot of second graders (and their parents) want to throw the pencil across the room. The reason it’s hard is that you’re doing two things at once: changing the numbers and subtracting. But once kids see why you borrow (you need more ones) and practice the routine enough times, it clicks. Here’s how to teach it so it sticks.

What is subtraction with borrowing?

Subtraction with borrowing (also called regrouping or decomposing) happens when you need to subtract a bigger digit from a smaller one. You can’t take 7 from 2, so you borrow 1 ten from the tens column, turn it into 10 ones, and add those 10 ones to the 2 you already have. Now you have 12 ones, and 12 minus 7 is easy.

This skill is a core part of 2nd grade math and maps directly to Common Core standard 2.NBT.B.5, which asks students to fluently add and subtract within 100 using place-value strategies. By the end of 2nd grade, kids should be able to solve problems like 52 - 28 without needing blocks or drawings.

The 4-step routine for subtraction with borrowing

This is the routine to teach, in this order, every single time:

Step 1: Start with the ones column

Always subtract the ones first. Look at the top digit and the bottom digit. If the top digit is bigger or the same, you can subtract right away. If the top digit is smaller, you need to borrow.

Step 2: Borrow 1 ten when you need it

When the top ones digit is too small, borrow 1 ten from the tens column:

Cross out the tens digit and write the number that’s 1 less.
Add 10 to the ones digit (write the new number above it).

For example, in 42 - 17:

The ones column is 2 minus 7. You can’t do that.
Borrow 1 ten from the 4 tens. Cross out the 4 and write 3.
Add 10 ones to the 2 ones. Write 12 above the 2.
Now the problem looks like 3 tens and 12 ones, minus 1 ten and 7 ones.

Step 3: Subtract each column

Now subtract the ones: 12 minus 7 equals 5. Write 5 in the ones place.

Then subtract the tens: 3 minus 1 equals 2. Write 2 in the tens place.

The answer is 25.

Step 4: Check your work by adding

This is the step kids skip, but it’s the one that builds confidence. Add the answer and the bottom number. If you get the top number back, you know it’s right.

For 42 - 17 = 25, check: 25 + 17 = 42. It works.

Why borrowing is confusing (and how to make it concrete)

The reason borrowing feels backwards is that the top number gets smaller in one column (the tens) and bigger in another (the ones). That’s weird if you’re only looking at the digits.

The way to make it make sense is to show the trade physically. Use base-ten blocks (or bundles of 10 popsicle sticks, or 10 pennies traded for a dime). When you borrow, have your child:

Take 1 ten rod and break it into 10 ones cubes.
Move those 10 ones over to the ones pile.
Now count: you have fewer tens and more ones, but the total amount hasn’t changed.

Once they’ve done this with blocks five or six times, the pencil-and-paper version starts to look like a shortcut for something they already understand.

The 3 mistakes kids make most (and how to fix them)

How to practice subtraction with borrowing at home

Practice works best when it’s short, daily, and tied to something real:

Shopping math: you have 50 dollars, the toy costs 28 dollars, how much is left?
Age problems: Grandma is 64, Mom is 38, what’s the difference?
Scorekeeping: one team has 42 points, the other has 17, how many more does the first team have?
Dice or cards: flip two cards to make each number, then subtract the smaller from the bigger.

Keep it to five or ten problems a day. When your child gets one wrong, don’t just show the answer. Give a hint (“Did you borrow? Did you change the tens digit?”) and let them try again. That second try is where the learning happens.

How to know your child has mastered it

Your child is ready to move on when they can:

Subtract two two-digit numbers with borrowing, accurately and without hesitating.
Explain why they borrowed (“I needed more ones”).
Check their work by adding and catch their own mistakes.
Solve a simple word problem that needs subtraction with borrowing.

Once those feel solid, the natural next steps are three-digit subtraction (which uses the same borrowing routine, just one more column) and word problems that mix addition and subtraction.

Free Double-digit Subtraction With Regrouping Worksheet

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The easiest way to give your child daily practice

For most parents, the hard part isn’t explaining borrowing. It’s finding enough of the right problems and keeping your child willing to do them. That’s where Octolearn helps: you describe the skill in plain language (“subtraction with borrowing”), and it generates a grade-matched practice set with read-aloud on every question, a hint and a second try before the answer, and stars and streaks that make kids want to come back tomorrow. It’s free to try, and it takes the daily practice off your plate so you can focus on the teaching.

Frequently asked questions

What grade do kids learn subtraction with borrowing?

Most children learn subtraction with borrowing (also called regrouping) in 2nd grade, when they work on fluently subtracting within 100 (Common Core standard 2.NBT.B.5). Some schools introduce it late in 1st grade. Kids are usually ready once they can subtract one-digit numbers confidently and understand that a number like 42 means 4 tens and 2 ones.

What does borrowing mean in subtraction?

Borrowing means taking 1 ten from the tens column and turning it into 10 ones so you have enough to subtract in the ones column. For example, in 42 minus 17, you can't take 7 from 2, so you borrow 1 ten from the 4 tens (leaving 3 tens) and add it to the 2 ones to make 12 ones. Then you can subtract 7 from 12.

Why is subtraction with borrowing so hard for kids?

It's hard because it asks kids to do three things at once: recognize when they need to borrow, change the numbers in two columns, and then subtract. The top number gets smaller in one place and bigger in another, which feels backwards. Using base-ten blocks to physically trade 1 ten for 10 ones makes the logic visible and much easier to understand.

Should I teach borrowing or the other subtraction strategies first?

Teach simpler subtraction first: problems where the top digit is bigger in every column, like 48 minus 23. Once that column routine feels automatic, introduce borrowing. Some teachers also show counting up or number line strategies, which can help kids check their borrowing work or solve problems mentally.

How can I practice subtraction with borrowing at home?

Keep practice short and real: subtract ages, prices, or game scores. Use base-ten blocks or bundled popsicle sticks for kids who need to see the trade happen. Do five to ten problems a day, give a hint before showing the answer, and celebrate when they catch their own mistake. Apps like Octolearn generate grade-matched sets with read-aloud and hints built in.