Math On

Speed comes from strategies, not effort

Fast mental arithmetic is less about thinking harder and more about knowing a few shortcuts well. Math On rewards accuracy with a combo multiplier, so one wrong answer costs far more than a slow one. The goal is reliable methods you can run without hesitating, then gradually faster execution of those methods.

Addition and subtraction shortcuts

Round and adjust. To add 58 and 37, add 60 and 37 to get 97, then take away the 2 you borrowed: 95. To subtract 199 from 452, subtract 200 and add 1 back: 253. Most people find numbers ending in 0 far easier, so turning an awkward number into a round one and correcting afterwards is the single most useful trick.

Work left to right. Schools teach column arithmetic from the right, but in your head it is quicker to add the tens first, then the units: 46 plus 38 is 70 plus 14, which is 84. You also get a close estimate straight away, which helps you notice a mistake.

Multiplication and division

Split one number into easy parts. 7 times 16 is 7 times 10 plus 7 times 6, so 70 plus 42 makes 112. Multiplying by 5 is the same as multiplying by 10 and halving: 5 times 48 is 480 halved, 240. Multiplying by 9 is multiplying by 10 and subtracting once: 9 times 23 is 230 minus 23, 207.

For division, check the times tables backwards and halve when you can. 144 divided by 4 is 144 halved twice: 72, then 36. A quick check of the last digit also helps: an even number times anything is even, and a number times 5 always ends in 0 or 5, so an answer that breaks those rules is wrong.

Squares, roots and percentages

Squares of numbers ending in 5 follow a pattern: take the tens digit, multiply it by the next number up, and put 25 on the end. 35 squared is 3 times 4, which is 12, followed by 25, giving 1225. Knowing the squares up to 20 by heart makes square roots quick, because you can recognise them in reverse.

Percentages become easy once you remember that 10 percent is dividing by ten and 1 percent is dividing by a hundred. 15 percent of 80 is 10 percent (8) plus 5 percent (4), making 12. Percentages can also be swapped round: 8 percent of 50 is the same as 50 percent of 8, which is 4.

Training with the modes

Zen has no timer, so it is the right place to practise a new trick until it feels automatic. Time Attack gives sixty seconds and rewards a steady rhythm over bursts of speed. Sudden Death and Endless punish mistakes, so they are good tests of accuracy. Raise the difficulty dial one step at a time: the jump from one level to the next is where the new strategies get tested, and a small step keeps your combo, and your confidence, intact.

Is Math On free?

Yes, it is free to play. An optional one-time purchase removes ads.

Can I play offline?

Yes. Math On plays great offline, and sign-in only syncs your progress across devices.

Is it good for kids?

Yes. There is a kid mode and colourblind-friendly colours, so it suits younger players too.