NumberP6 level25 questions in the full course

A building block for the test. SEAG doesn't test this topic on its own, but questions on tested topics rely on it. If it's shaky, it's worth securing, without spending long on it.

Subtraction Facts Within 20SEAG Practice Questions

Quickly recall subtraction facts within 20.

Where your child meets this in real life: Making change, calculating differences, or solving problems quickly

What your child needs to know

In the SEAG test

This topic isn't tested on its own, but it sits inside questions on tested topics. Each SEAG paper has 28 maths questions. Questions 29 to 50 are multiple choice with five possible answers, and questions 51 to 56 need a short written answer. With 56 questions in 60 minutes across English and maths, that is about a minute per question.

SEAGReady breaks subtraction facts within 20 into 3 steps, taught in order so each skill builds on the last.

1
Within 10
Recall subtraction facts where both numbers are 10 or less (e.g., 9 - 4 = 5)
2
From Teens, No Crossing
Subtract from numbers 11-20 where the result stays in the teens (e.g., 17 - 4 = 13)
3
Crossing 10
Subtract from numbers 11-20 where the result crosses back through 10 (e.g., 15 - 8 = 7)

Try these SEAG-style questions

Try three free questions from our subtraction facts within 20 course. They start easy and get harder, so you can see where your child's confidence runs out. If they manage the last one without a hint, this topic is probably secure. If not, the steps above show where to start.

Question 1Confidence builder

Oliver has 8 apples. He gives 3 to his friend Sarah. How many apples does Oliver have left?

Question 2Standard

Sarah has 19 books on her shelf. She takes 6 to school. How many books are left on the shelf?

Question 3Stretch

Sean has 16 conkers. He gives some away and has 7 left. How many conkers did Sean give away?

Try the lesson: Within 10

This is the exact interactive worked example your child sees in SEAGReady. Step through it and watch the method build up.

Amy has 9 sweets. She gives 4 to her brother Luke.

How many sweets does Amy have left?

9 − 4

Show what happens

1

Start with Amy's 9 sweets.

9

Step 1 of 4

Prefer to read? See every step written out

Amy has 9 sweets. She gives 4 to her brother Luke.

How many sweets does Amy have left?

1
Show what happens
- Start with Amy's 9 sweets.9
- Cross out the 4 sweets Amy gives to Luke.9 − 4
2
Count what remains
- Five counters are not crossed out, so 5 sweets remain.
- Write the complete subtraction fact.9 − 4 = 5

Amy has 5 sweets left.

The key insight: Subtraction and addition are opposites! If you know 4 + 5 = 9, you also know 9 − 4 = 5.

Common mix-up: Counting back on fingers and losing track. Using addition facts is faster and more reliable than counting backwards.

Mistakes to watch for

These are the misconceptions we see most often in subtraction facts within 20, including the ones our practice questions are specifically designed to catch.

Not seeing link to addition facts
Counting back inefficiently
Errors when crossing 10 (e.g., 15 - 8)

Build these skills first

Struggling with subtraction facts within 20? The real gap is often in one of these earlier topics.

Addition Facts to 20

More number practice

Read & Write Whole Numbers Identify Place Value of a Digit Compare Two Whole Numbers Order a Set of Whole Numbers Add 2-Digit Numbers (No Carry)Add 2-Digit Numbers (With Carry)

25 questions on this topic alone

Master subtraction facts within 20 and everything it unlocks

SEAGReady finds the exact step where your child gets stuck, teaches it with worked examples like the one above, and brings it back for review so it sticks.

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