How to Teach Subtraction to Kids, Step by Step

At what age do children learn subtraction?

Subtraction grows alongside addition, usually a step behind it; US standards expect fluent subtraction within 100 by the end of 2nd grade. England's Year 1 is for ages 5–6, a year younger than US 1st grade, so the table compares by age.

Subtraction by age: US Common Core and England's national curriculum
Age	US (Common Core)	England (national curriculum)
5–6	Kindergarten: take away and take apart within 10 with objects or drawings; fluent within 5	Year 1: subtraction facts within 20 that go with number bonds; subtract one- and two-digit numbers to 20, including 0
6–7	1st grade: subtract within 20 using strategies such as getting to 10 and related addition facts; fluent within 10; subtract tens (70 − 30)	Year 2: facts to 20 fluently; subtract with two-digit numbers; check subtraction by adding
7–8	2nd grade: fluent within 20 and within 100; within 1,000 with models	Year 3: written column subtraction, up to 3 digits
8–10	3rd–4th grade: fluent within 1,000, then the standard written method for larger numbers	Year 4: column subtraction, up to 4 digits

If a step feels hard, go back a step and use objects again. For the wider picture, see math skills by age.

Take away or find the difference? Teach both

Most children meet subtraction as taking away: “You had 7 grapes and ate 2. How many are left?” That is a great start. But subtraction also answers a second question: “How many more?” or “What is the difference?” Children who only know take-away get confused by comparison questions.

Example Two questions, one subtraction

Take away: 9 cookies, eat 3 → 9 − 3 = 6 left
Difference: Sam has 9 stickers, Ben has 6 → 9 − 6 = 3 more
Missing part: 6 + ? = 9 → 3

To show a difference, stand Lego towers of 9 and 6 bricks side by side. The 3 bricks sticking out are the difference: nothing is taken away, yet the answer is 9 − 6 = 3. England's DfE guidance teaches this idea explicitly in Year 2, with questions worded “how many more” and “how many fewer”.

Tip Watch the word “more”

In “Sam has 9 stickers. That's 3 more than Ben. How many does Ben have?”, the word “more” tempts children to add (9 + 3 = 12), but the answer is 9 − 3 = 6. The Common Core standards note that problems worded like this are harder. Act them out rather than hunting for key words.

Step by step: from taking away to regrouping

As with addition, go from objects to drawings, such as a number line, to written sums. The What Works Clearinghouse recommends the number line as a core tool: 8 − 5 is the distance from 5 to 8, which is 3 steps.

Take away with objects (within 10). Put out 8 grapes, eat 3 and count what's left: 5. Say it: “8 take away 3 is 5.”
Count back for small numbers. For 9 − 2, start at 9 and count back 2: “eight, seven.” On a floor number line, your child jumps back 2 steps.
Use number bonds. A child who knows 7 + 3 = 10 also knows 10 − 3 = 7 and 10 − 7 = 3.
Count up when the numbers are close. For 12 − 9, count up from 9: 10, 11, 12. That's 3 jumps, so 12 − 9 = 3, far quicker than 9 steps back.
Subtract through 10. For 13 − 5, take away 3 to reach 10, then 2 more: 13 − 3 − 2 = 8.
Two-digit numbers, no regrouping. For 47 − 23, take the tens, then the ones: 47 − 20 = 27, then 27 − 3 = 24.
Two-digit numbers with regrouping. When there aren't enough ones, swap 1 ten for 10 ones (see below).

Example Worked examples

Count back: 9 − 2 → 9… 8, 7 → 7
Count up: 12 − 9 → 9… 10, 11, 12 → 3 jumps → 3
Through 10: 13 − 5 = 13 − 3 − 2 = 10 − 2 = 8
Think addition: 14 − 6 → 6 + 8 = 14 → 8
Tens, then ones: 47 − 23 = 47 − 20 − 3 = 27 − 3 = 24

Tip Count the jumps, not the numbers

Children often include the start number when counting back, so 9 − 3 becomes “9, 8, 7”. The answer is where you land after 3 jumps: 8, 7, 6. Jumping along a tape line on the floor makes this easy to feel.

Subtraction is addition in reverse

Addition and subtraction undo each other. Three numbers such as 5, 8 and 13 make a “fact family” of four facts. US standards build this link in 1st grade (subtract 10 − 8 by finding what makes 10 with 8), and England's curriculum has children check subtraction by adding in Year 2.

Example One fact family: 5, 8 and 13

5 + 8 = 13
8 + 5 = 13
13 − 5 = 8
13 − 8 = 5

A part–whole picture helps: draw a circle with 13 (the whole) joined to two circles with 5 and 8 (the parts). Cover any number and ask your child to find it. The whole minus one part always leaves the other part.

Fact family houses

Ages: 6–8
Time: 10 min
You need: Paper, a pen and 20 beans or buttons

Draw a house with a total in the roof, for example 12, and two windows below.
Your child splits 12 beans into two groups and writes the parts in the windows, for example 7 and 5.
Write the four facts under the house together: 7 + 5 = 12, 5 + 7 = 12, 12 − 7 = 5, 12 − 5 = 7.
Cover one window with your thumb and ask: “What's hiding?”

Regrouping (borrowing), explained with Lego

Regrouping is what many parents learned as borrowing; schools in England say exchanging. It's needed when a column has too few ones to take away. US children use it within 100 in 2nd grade and use the standard written method fluently in 4th grade; in England, the formal column method comes in Year 3.

Build 52: 5 towers of 10 bricks and 2 single bricks.
You need to take away 7 single bricks, but there are only 2.
Break one tower into 10 single bricks. Now there are 4 towers and 12 single bricks, which is still 52.
Take away 7 single bricks: 12 − 7 = 5.
Take away 2 towers: 4 − 2 = 2.
Read the answer: 2 towers and 5 single bricks make 25. Check by adding: 25 + 27 = 52.

Example The same steps in columns

Ones: 2 − 7 won't work, so regroup 52 as 40 + 12
Ones: 12 − 7 = 5
Tens: 4 − 2 = 2
Answer: 52 − 27 = 25

Mental routes work too: keep the first number whole, so 52 − 20 = 32, then 32 − 7 = 25. Or count up from 27: 3 to reach 30, 20 more to 50 and 2 more to 52, so 3 + 20 + 2 = 25.

Tip Don't split both numbers

Splitting both numbers works for addition but backfires in subtraction. For 63 − 17 it is tempting to do 60 − 10 = 50 and 7 − 3 = 4, giving 54. England's DfE guidance advises against this because it leads to errors. Keep 63 whole instead: 63 − 10 = 53, then 53 − 7 = 46.

Common mistakes (and quick fixes)

Taking the smaller digit from the bigger one. 52 − 27 becomes 35 because 7 − 2 feels easier than 2 − 7. Fix: estimate first (about 50 − 30 = 20, so 35 is too big), then build it with Lego.
Forgetting the ten has gone. In 61 − 18, the child regroups to 11 − 8 = 3 but keeps 6 tens and writes 53. Fix: cross out the 6 and write 5 the moment a tower is broken. The answer is 43.
Zeros. 40 − 17 can become 37 (7 − 0 = 7). Fix: 40 is 4 towers and no single bricks, so a tower must be broken first: 10 − 7 = 3 ones, 3 − 1 = 2 tens, so 23.
Including the start number when counting back. 9 − 3 comes out as 7 instead of 6. Fix: count jumps on a number line.
Turning subtraction around. 3 − 8 is not the same as 8 − 3. Fix: show with grapes that you can't take 8 from 3. England's curriculum teaches this in Year 2.
Adding when they see “more”. See the comparison tip above: act it out with towers.

A 5-minute routine (and 2 games)

Count back (1 minute): “Start at 15 and count back 4” (14, 13, 12, 11).
Addition to subtraction (1 minute): “If 6 + 4 = 10, what is 10 − 4?”
One difference question (1 minute): “You're 7 and your cousin is 4. How many years older are you?” (3)
One regrouping problem with Lego, from about age 7 (2 minutes): 34 − 18 = 16.
End on an easy win.

Bottle bowling

Ages: 5–7
Time: 10 min
You need: 10 empty plastic bottles and a soft ball

Stand the 10 bottles up like bowling pins.
Roll the ball and count the bottles that fell, for example 4.
Before counting the rest, ask: “How many are still standing?” Then say it: “10 take away 4 is 6.”
Older children start on 30 points and subtract the fallen bottles each time.

Race back to zero

Ages: 6–8
Time: 10 min
You need: Masking tape or chalk for a 0 to 20 number line, 1 die and a toy for each player

Both players start on 20.
Roll the die, jump back that many steps and say the subtraction: “20 − 4 = 16.”
You must land exactly on 0 to win. If a roll would take you past 0, miss that turn.
Harder: start at 50 on a paper number line and roll two dice.

More screen-free ideas are in our math games guide, and fast strategies are in mental math for kids.

When to talk to the teacher

Talk to the teacher if these persist after a few weeks of short, regular practice:

near the end of 1st grade, subtraction facts within 10 still need finger counting every time;
in 2nd or 3rd grade, regrouping errors keep coming back even after work with objects;
the link to addition (8 + 5 = 13, so 13 − 5 = 8) never seems to click;
your child is anxious about math or avoids it (see math anxiety in kids).

Ask which method the class uses for two-digit subtraction (counting up, number lines or columns) and use the same one at home.

Frequently asked questions

What is the easiest way to teach subtraction?

Start with real objects and taking away: 8 grapes, eat 3, 5 left. Then teach counting back for small numbers, counting up when the numbers are close, and the link to addition (7 + 3 = 10, so 10 − 3 = 7).

What is the difference between borrowing and regrouping?

They are the same thing. Regrouping is today's US term, borrowing is the older word and schools in England say exchanging; all mean swapping 1 ten for 10 ones so there are enough ones to subtract.

Is counting back or counting up better?

Both are useful. Count back when taking away a small number (15 − 3) and count up when the two numbers are close (15 − 12), because counting up from 12 to 15 takes only 3 steps.

Why does my child add when a question says “how many more”?

Many children learn that “more” means add. In comparison questions, “how many more” asks for the difference, which is a subtraction. Acting the problem out with two towers of blocks shows what is really being asked.

At what age do children subtract two-digit numbers?

In the US, children subtract tens such as 70 − 30 in 1st grade and are expected to subtract within 100 fluently by the end of 2nd grade, at about age 8. In England, written column subtraction is taught in Year 3, at age 7–8.

How can my child check a subtraction answer?

By adding. If 52 − 27 = 25, then 25 + 27 should give 52; if it doesn't, something went wrong.

Sources

Written by the Matobur team at Edict Digital and checked against these sources:

Common Core State Standards for Mathematics (Kindergarten to Grade 4, incl. Table 1: addition and subtraction situations) (opens in a new tab)National Governors Association Center for Best Practices and Council of Chief State School Officers
National curriculum in England: mathematics programmes of study (opens in a new tab)UK Department for Education
Mathematics guidance: key stages 1 and 2 (Teaching mathematics in primary schools) (opens in a new tab)UK Department for Education
Assisting Students Struggling with Mathematics: Intervention in the Elementary Grades (practice guide, 2021) (opens in a new tab)Institute of Education Sciences, What Works Clearinghouse (US Department of Education)

How to Teach Subtraction: A Step-by-Step Guide for Parents

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