How to Teach Subtraction With Borrowing (Regrouping)

Borrowing — or regrouping — is where subtraction gets tricky for many children. This guide breaks it down, step by step.

Subtraction with borrowing is one of the first math skills where a child has to hold several ideas in their head at once, and it is also one of the most common places for confidence to wobble. The good news is that borrowing is not really a new rule to memorize at all. It is just a different way of looking at the number your child already understands. This guide walks you through what borrowing actually means, how to explain it with objects and words that make sense to a 7 to 10 year old, and how to spot and fix the mistakes that trip kids up most.

What "borrowing" and "regrouping" really mean

You may hear the words borrowing and regrouping used for the same thing. Many classrooms now prefer "regrouping" because it describes the idea more honestly: you are not really borrowing something you have to pay back, you are regrouping a number so it is easier to subtract.

Everything depends on place value. In the number 52, the 5 is not simply "five" — it stands for 5 tens, or 50. The 2 stands for 2 ones. A two-digit number is a bundle of tens plus some loose ones. Regrouping means trading one of those tens for ten ones so you have enough ones to subtract from. The total value of the number never changes. You are only changing how it is packaged.

This is the single idea to anchor everything on: ten ones and one ten are exactly the same amount, just grouped differently. A child who truly believes that sentence will understand borrowing. A child who only memorizes "cross it out and put a little one next to it" will forget the steps by next week.

A worked example: 52 − 27, step by step

Let's work through 52 − 27 the way you would explain it out loud at the kitchen table.

1. Line the numbers up by place value. Ones under ones, tens under tens. Always start subtracting from the ones column on the right.
2. Look at the ones. We need 2 − 7. But we only have 2 ones, and we cannot take 7 away from 2. This is the signal that we need to regroup.
3. Trade one ten for ten ones. The 5 tens become 4 tens, and those 2 ones become 12 ones. Nothing has been lost: 4 tens (40) plus 12 ones is still 52. On paper, the 5 is crossed out and becomes 4, and the 2 becomes 12.
4. Subtract the ones now. 12 − 7 = 5. Write 5 in the ones place.
5. Subtract the tens. We now have 4 tens, and we take away 2 tens. 4 − 2 = 2. Write 2 in the tens place.
6. Read the answer. 52 − 27 = 25.

Ask your child to check it a different way: 25 + 27 should give back 52. Addition and subtraction undo each other, so this is a quick, honest way to prove the answer is right and it builds the habit of checking.

Make it concrete with objects first

Children understand borrowing with their hands long before they understand it on paper. Spend time here before rushing to the written method. A few options that work well:

• Base-ten blocks. Show 52 as 5 "ten-rods" and 2 "unit cubes." When you cannot give away 7 units, physically swap one ten-rod for 10 unit cubes. Now there are 4 rods and 12 units, and the child can simply take 7 units and 2 rods away. The trade is something they do, not something they memorize.
• Bundles of straws or craft sticks. Rubber-band ten straws into a bundle. To subtract, you literally snap the rubber band off one bundle to free ten loose straws. The "snap" is a moment kids remember.
• Money. This one clicks for a lot of children. A ten is a $10 bill; the ones are $1 coins. You cannot pay 7 dollars with only 2 coins, so you break the ten-dollar bill into ten ones at the "bank." Now paying is easy.

Whatever you use, say the regrouping out loud every time: "I don't have enough ones, so I'll trade one ten for ten ones." Hearing the same sentence tied to the same action is what moves the idea from fingers to paper.

Common mistakes and how to fix them

Most borrowing errors are predictable. Once you know them, you can catch them in seconds.

• Subtracting the smaller digit from the larger, whatever its position. In 52 − 27, a child who hasn't grasped regrouping will look at the ones, see 2 and 7, and just write 5 (7 − 2) because it's "easier." The fix: insist they always ask "do I have enough to subtract?" before writing anything, and go back to blocks so they feel why the direction matters. The top number is what we have; we can't take away more than we have without regrouping.
• Forgetting to reduce the tens. They borrow ten ones but leave the tens digit unchanged, so 52 − 27 comes out as 35 instead of 25. The fix: physically cross out the 5 and write 4 before doing the ones subtraction, so the reduced ten is already on the page.
• Borrowing across a zero. A problem like 305 − 148 stalls kids because the tens place is 0 — there is no ten to borrow from directly. The fix: regroup in two steps. Borrow from the hundreds first (3 hundreds becomes 2 hundreds, the 0 tens becomes 10 tens), then borrow one of those tens for the ones (10 tens becomes 9 tens, 5 ones becomes 15 ones). Walking through this slowly with blocks, a couple of times, usually clears it up.
• Messy columns. Surprisingly often the math is fine but the digits drift out of alignment and ones get added to tens. Grid or graph paper, one digit per box, prevents a lot of "wrong" answers that were never really arithmetic errors.

How to practice: little and often

Short, frequent practice beats a long weekend drill every time. Five to ten focused minutes a day will do more than an hour once a week, because the skill needs to settle into memory with rest in between. A few tips:

• Start with problems that need no borrowing, mix in a few that do, then gradually raise the proportion. Early wins keep confidence up.
• Have your child explain one problem out loud to you each day. If they can teach the trade, they own it.
• Keep the checking habit: add the answer back to the number you subtracted.
• Praise the process ("you noticed you didn't have enough ones") rather than just a correct answer. That is what makes a child willing to try the hard ones.

Practice subtraction with free worksheets

When your child is ready to practice on paper, varied problems help the skill stick without turning into a worksheet marathon. You can print ready-made Grade 2 math worksheets that build gently from no-regrouping to borrowing, or use our free worksheet generator to make a fresh page at exactly the level you want, with an answer key for quick checking. Browse more math worksheets for related skills like place value and addition with carrying, which reinforce the same ideas from the other direction.

Borrowing feels like a hurdle, but it rewards patience. Keep the blocks nearby, keep the sessions short, and keep saying the trade out loud. Once the idea that "ten ones equals one ten" is genuinely believed, the little crossed-out digits stop being a mystery and become something your child can explain back to you — which is the surest sign they've got it.