🔢 Mathematics · Addition & Subtraction

Adding and subtracting

Add and subtract one-digit and two-digit numbers to 20, including zero

Typical age: 5–6 years

“Can your child work out sums like '14 + 5' or '18 − 6' in their head or on paper, and do they know that adding or taking away zero leaves the number unchanged?”

0 / 3 mastered

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Needs first

Number bondsREQUIRED
Adding/subtracting to 20 procedurally requires knowing the number bonds

Unlocks next

Mental addition and subtraction (age 6+)REQUIRED
Adding ones to a two-digit number extends Y1 adding within 20
Early Word ProblemsREQUIRED
Word problems to 20 require the procedural ability to add/subtract to 20