SEAGReady
NumberP6 level25 questions in the full course
Supporting practice: this topic helps build angle understanding, but it is not selected for official-format mocks.Subtraction facts to 20 are a necessary fluency prerequisite, but the Northern Ireland progression pathway places this explicit outcome before Key Stage 2 rather than in current SEAG assessed scope.

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

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

  1. 1

    Within 10

    supporting lesson — excluded from official-format mocks

    Recall subtraction facts where both numbers are 10 or less (e.g., 9 - 4 = 5)

  2. 2

    From Teens, No Crossing

    supporting lesson — excluded from official-format mocks

    Subtract from numbers 11-20 where the result stays in the teens (e.g., 17 - 4 = 13)

  3. 3

    Crossing 10

    supporting lesson — excluded from official-format mocks

    Subtract from numbers 11-20 where the result crosses back through 10 (e.g., 15 - 8 = 7)

Try these SEAG-style questions

Three free sample questions from our subtraction facts within 20 course. Every question comes with a full explanation, and hints that guide without giving the answer away.

Question 1Confidence builder

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

A ten-frame contains eight apple counters, with three crossed out and no remaining total stated.
Answer choices for question 1
Question 2Confidence builder

Kyle has 16 football stickers. He gives 3 of them to his friend. How many stickers does Kyle have now?

Two ten-frames contain sixteen football-sticker counters, with three crossed out and no remaining total stated.
Answer choices for question 2
Question 3Confidence builder

Poppy baked 14 biscuits for a school fair. Her family ate 7 before she could take them. How many biscuits does Poppy have left for the fair?

Two ten-frames contain fourteen biscuit counters, with seven crossed out across ten and no remaining total stated.
Answer choices for question 3

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. 1

    Show what happens

    • Start with Amy's 9 sweets.9
    • Cross out the 4 sweets Amy gives to Luke.9 − 4
  2. 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 NumbersIdentify Place Value of a DigitCompare Two Whole NumbersOrder a Set of Whole NumbersAdd 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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