Year 2 Addition and Subtraction: A Complete Guide

Year 2 addition and subtraction takes everything secured in Year 1 and extends it to two-digit numbers — while also introducing the idea that known facts can be reused to work out new ones, rather than everything being calculated from scratch.

What's actually covered

• Recalling addition and subtraction facts to 20 fluently, and deriving related facts to 100 (6 + 7 = 13, so 60 + 70 = 130).
• Adding and subtracting a two-digit number and ones (34 + 5).
• Adding and subtracting a two-digit number and tens (34 + 20).
• Adding and subtracting two two-digit numbers (34 + 27).
• Adding three one-digit numbers (4 + 7 + 3), which starts building an awareness of which pairs to combine first for ease.
• Solving problems with addition and subtraction, including missing-number problems, applying increasingly efficient mental strategies.

Using known facts, not just counting

This is the real shift in Year 2: a child who knows 8 + 5 = 13 should be able to work out 28 + 5 without recalculating from the beginning, by recognising that only the ones digit changes. This "known fact to new fact" strategy is one of the most useful mental maths habits a child can build, and it's worth actively encouraging rather than assuming it develops automatically from repeated practice alone.

Where exchanging first causes trouble

Two-digit subtraction that requires "exchanging" — 42 − 17, where you can't simply take 7 from 2 — is genuinely one of the bigger jumps in Year 2. It requires understanding place value well enough to know that a ten can be "broken up" into ten ones, which is a more abstract idea than most of what's come before it. Children who are shaky here often aren't struggling with subtraction itself; they're struggling with the underlying place value concept the method depends on.

How to help at home

Base-10 blocks, or even just bundles of ten straws with loose ones, make exchanging concrete in a way that numbers on a page often don't. Physically "breaking" a bundle of ten into ten single straws to show why 42 becomes "3 tens and 12 ones" before subtracting 17 tends to make the written method click far faster than repetition of the written method alone.

For everyday practice, asking "what's 34 plus 5?" immediately followed by "so what's 34 plus 6?" gets a child using known facts rather than recalculating — a habit that pays off well beyond Year 2.

This is the principle behind Grasp Maths

Grasp Maths distinguishes exchanging-based subtraction from simple two-digit subtraction as separate skills, so if a child is fine without exchanging but stumbles the moment it's needed, that's exactly where the next practice gets targeted — not another round of the easier version they've already mastered.

Looking for printable practice too? See our Year 2 maths worksheets, or read the full Year 2 maths overview.