Grown-ups
6 – 10 years

Math Ninja

Number basics and sneaky mental-math tricks!

  • Confidence

What it is

Math Ninja has two doors, and Otto the octopus, in his ninja headband, says what to do. Number Basics is ten levels of practice, from counting to ten up to times tables and division, with pictures that carry the idea: ten-frames of dots for small sums, rows of dots for multiplication, groups for sharing. Ninja Tricks teaches twenty real mental-arithmetic shortcuts, the kind adults use without noticing: rounding to a friendly number, making tens, adding 9 by adding 10 and sliding back, doubling and halving, the 11 rule. Each trick is taught three ways: watch a worked example unfold, do one together step by step, then five on your own. A wrong answer gets a hint and a second go, never a game over.

How to play

On a laptop or desktop

Type the answer and press Enter. In a lesson, Space skips ahead through the worked example.

On a tablet or phone

Tap the digits on the number pad, then the green check. Tap a step to hurry the demonstration.

What children learn

Tips for parents

Do the Watch phase together once and say the steps out loud. The tricks stick when a child can explain why they work, not just that they do. The Solo phase has a peek button that shows the steps at the cost of a star.

Questions parents ask

Which tricks are included?

Friendly numbers, left-to-right adding, making tens, plus 9, doubles plus one, add-up-to-subtract, shifting both numbers, all-from-9-last-from-10, minus 9, dropping to a ten, double and halve, the 11 rule, times 5, times 9, double-double for times 4, times 15, squaring numbers ending in 5, dividing by 5, halving twice for dividing by 4, and chunking.

Is it suitable for a six-year-old?

Number Basics is. The tricks assume comfort with two-digit numbers and are best from about eight.

Are the problems the same every time?

No. Every problem is generated fresh, but always with numbers where the trick actually applies, so the child sees the pattern rather than memorizing an answer.

Read the guide20 Mental Math Tricks for Kids, Explained Step by StepThe twenty mental-arithmetic shortcuts taught in Math Ninja, each with a worked example and the reason it works. For ages 7 to 10.

More games for ages 6 to 10

Spell It Out4 – 7 yearsMemory Match2 – 10 yearsMelody Maker3 – 7 years
Play Math Ninja now