How to teach subtraction to kids, step by step

Quick answer

Teach subtraction in stages: take away objects, compare two groups (“how many more?”), then count back and count up on a number line. Next, use fact families to “think addition” (12 − 9: 9 plus what makes 12?), get to 10 first for teen facts, then subtract tens and two-digit numbers. Common Core expects fluency within 5 in kindergarten, 10 in 1st grade, and 20 and 100 in 2nd grade.

Subtraction trips up more children than addition, and not because they aren't trying. It has three meanings (taking away, comparing, and finding a missing part), order matters, and counting backward feels less natural than counting forward. The fix: move through clear stages, from objects to pictures to numbers, and connect every subtraction fact to an addition fact your child already knows.

What to expect by grade

Here is what the Common Core State Standards, used by most U.S. states, expect by the end of each grade. Your state or school may differ a little.

Step 1: Take away real objects

Start with the meaning kids understand best: taking away. Put 7 crackers on a plate, eat 3, and count what's left. Say it in math words: “7 take away 3 leaves 4.” Then move to drawings: draw 7 circles and cross out 3.

Teach the words that signal subtraction: take away, minus, left, fewer, less, difference. Kindergarten story problems sound like this: “There were 8 birds on the fence. 2 flew away. How many are still there?”

Step 2: Compare two groups

Subtraction also answers “How many more?” and “How many fewer?” Nothing is taken away here, which surprises many kids. Maya has 8 stickers and Leo has 5. Line them up in pairs: 5 of Maya's stickers match Leo's, and 3 have no partner. Maya has 3 more, so 8 − 5 = 3.

Comparing shows up all the time: who has more grapes, or how many more days until a birthday.

Step 3: Count back on a number line

Once your child can count backward, show them how to count back. For 9 − 3, start at 9 and take 3 jumps back: 8, 7, 6.

The number line is one of the tools recommended in the U.S. Institute of Education Sciences guide on helping students who struggle with math. Counting back works best for small numbers like 1, 2 or 3. For 15 − 12, counting back 12 times is slow and error-prone, so kids need the next step.

Step 4: Count up and think addition

Subtraction can also be a missing-number problem. Common Core says it directly: understand subtraction as an unknown-addend problem, for example finding 10 − 8 by asking what number makes 10 when added to 8 (1.OA.B.4). For 12 − 9, start at 9 and count up to 12: that's 3 jumps, so 12 − 9 = 3.

This is where fact families help. The numbers 5, 8 and 13 make four facts. If your child knows 5 + 8 = 13, they also know 13 − 8 = 5 and 13 − 5 = 8.

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

Ask “What plus 8 makes 13?” instead of “What's 13 minus 8?” and many children find the answer much faster. Our guide to fact families has triangle cards and games for this.

Step 5: Get to 10 first for teen facts

For facts like 13 − 4, a quick strategy is to stop at 10 on the way down. Break 4 into 3 and 1: 13 − 3 = 10, then 10 − 1 = 9. Common Core uses this exact example for 1st grade (1.OA.C.6).

A second version is take from ten. For 13 − 8, think of 13 as a ten and 3 ones. Take the 8 from the ten, which leaves 2, then put the 3 back: 2 + 3 = 5.

+

Both rely on knowing the pairs that make 10, so the make ten strategy and these subtraction strategies are best taught side by side.

Step 6: Subtract tens, then two-digit numbers

Bigger numbers work the same way once kids think in tens and ones. 70 − 30 is just 7 tens take away 3 tens, which is 4 tens: 40. Finding 10 less (74 − 10 = 64) should become automatic in 1st grade (1.NBT.C.5).

For 58 − 23, build 58 with base-ten blocks, take away 2 tens and 3 ones, and 3 tens and 5 ones are left: 35. Then show the same steps in columns, ones first.

58−2335

Sometimes there aren't enough ones, as in 52 − 27. Then you trade 1 ten for 10 ones. That's regrouping, or “borrowing,” and it has its own step-by-step guide.

41252−2725

Step 7: Build fluency with games and short practice

Fluency means answering accurately and flexibly, not only fast. The U.S. Institute of Education Sciences recommends spacing practice over time and using quick quizzing, so keep sessions to 5–10 minutes and bring missed facts back a few days later. Games make it painless:

• Bowling. Set up 10 plastic bottles. After each roll, ask how many fell and how many are still standing (10 − 4 = 6).
• Subtraction war. Each player flips two cards (face cards removed) and subtracts the smaller from the bigger. The biggest difference wins the round.
• Snack math. “You have 9 grapes. If you eat 3, how many are left?”
• Countdown stairs. Count backward as you walk down the stairs, then try starting from 20.

Common mistakes (and how to help)

• Counting the starting number. For 9 − 3 a child says “9, 8, 7” and answers 7. Use the number line: the jumps are what you count, not the numbers you stand on.
• Subtracting the smaller digit from the bigger one. In 52 − 27, a child does 7 − 2 = 5 and writes 35. The top number always comes first; if there aren't enough ones, regroup.
• Turning numbers around. 5 − 3 = 2, but 3 − 5 is not 2. Subtraction has no turnaround rule. (3 − 5 is a negative number, which children meet in middle school.)
• Trusting key words. “Sam has 8 stickers. That's 3 more than Ana. How many does Ana have?” The word “more” appears, but the answer is 8 − 3 = 5. Act out the story with toys before choosing an operation.

Practice problems

Try these together and ask which strategy your child used: take away, count back, count up or get to 10.

Subtraction practice (with answers)

1. 5 − 2 = ?
2. 7 − 3 = ?
3. 10 − 6 = ?
4. 9 − 4 = ?
5. 12 − 9 = ?
6. 13 − 4 = ?
7. 15 − 8 = ?
8. 16 − 7 = ?
9. 70 − 30 = ?
10. 74 − 10 = ?
11. 58 − 23 = ?
12. 52 − 27 = ?

Show answers

Want more? Print our free subtraction worksheets or a set of ten-frames. For grade-by-grade goals, see our kindergarten, 1st grade and 2nd grade checklists, and for the addition side of every fact, our guide on how to teach addition.

Frequently asked questions

How do I teach subtraction to a kindergartener?

Use objects and stories. Line up 6 toy cars, drive 2 away and ask how many are left. Count together, then say it as “6 take away 2 is 4.” Stay within 10 and lean on fingers, snacks and drawings. The Common Core kindergarten goal is to subtract fluently within 5 (K.OA.A.5).

How do you teach subtraction to grade 1?

First graders work within 20 using strategies: counting back, counting up, thinking of the related addition fact, and getting to 10 first (13 − 4 = 13 − 3 − 1). Use a number line and ten-frames, practice fact families, and aim for fluency within 10 by the end of the year (1.OA.C.6).

What is counting back in subtraction?

Counting back means starting at the bigger number and counting backward one number for each one you take away. For 9 − 3, start at 9 and say “8, 7, 6,” so the answer is 6. It works well when the number being subtracted is small, such as 1, 2 or 3.

Should my child count back or count up to subtract?

Both. Counting back is quick when you take away a small number (15 − 2). Counting up is quicker when the two numbers are close together (15 − 12: from 12, count 13, 14, 15, which is 3). Teaching both helps children pick the faster path instead of counting back a long way.

Why is subtraction harder than addition for many kids?

Subtraction has several meanings (taking away, comparing, finding a missing part), order matters (5 − 3 is not the same as 3 − 5), and counting backward feels less natural than counting forward. Connecting each subtraction fact to the addition fact children already know makes it much easier.

When should kids know subtraction facts?

Common Core expects fluency within 10 by the end of 1st grade (1.OA.C.6) and fluency within 20 using mental strategies by the end of 2nd grade (2.OA.B.2), along with fluency within 100 (2.NBT.B.5). Your state or school may differ, and practicing both operations together helps.

Sources

• Common Core State Standards: Kindergarten, Operations & Algebraic Thinking — CCSSI
• Common Core State Standards: Grade 1, Operations & Algebraic Thinking — CCSSI
• Common Core State Standards: Grade 1, Number & Operations in Base Ten — CCSSI
• Common Core State Standards: Grade 2, Operations & Algebraic Thinking — CCSSI
• Common Core State Standards: Grade 2, Number & Operations in Base Ten — CCSSI
• Common Core State Standards: Grade 3, Number & Operations in Base Ten — CCSSI
• Assisting Students Struggling with Mathematics: Intervention in the Elementary Grades (practice guide) — Institute of Education Sciences, What Works Clearinghouse
• Organizing Instruction and Study to Improve Student Learning (practice guide) — Institute of Education Sciences, What Works Clearinghouse

Written by The Mathing Team for parents and teachers. Grade expectations follow the Common Core State Standards for Mathematics; your state or school may sequence skills a little differently.