How to Do Mental Math Addition

Start with partners of ten

Before large sums, children need automatic number bonds to 10. When 7 + 3 is instant, 27 + 3 and 47 + 8 become much calmer. Practice this in Making Tens.

Left-to-right addition

For 53 + 26, add tens first (50 + 20 = 70), then ones (3 + 6 = 9), then combine (79). This matches how we say numbers and reduces working-memory load compared with ones-first carrying for many learners.

Bridge through a ten

When a sum crosses a ten boundary — like 28 + 7 — land on the ten first (28 + 2 = 30), then add the leftover (30 + 5 = 35). Bridging keeps the path short and visible.

A weekly practice recipe

1. Three minutes of make-ten flash questions
2. Five left-to-right two-digit sums
3. One game of Speed Round