About Sum Race
Sum Race is mental arithmetic as a sprint. The same sum is shown to both players at once, and whoever taps the correct answer first takes the point.
How a match works
Each sum is either an addition of two numbers up to thirty, or a multiplication from the times tables up to nine. Three possible answers appear on each player's side. They are the same three numbers for both players, shuffled separately, so neither can copy the other's position.
Get it right first and you score. Get it wrong and your buttons are frozen for a second and a half, which is usually long enough for your opponent to work it out in peace. The first to five points wins.
Sitting and setting up
Lay the device flat between you. The sum is printed twice in the middle, once facing each player. On a computer, player one presses 1, 2 or 3 and player two presses 8, 9 or 0, matching the buttons from left to right.
How to win
Look at the answers before you finish the sum. Often two of the three can be ruled out at a glance. If the sum is 7 × 8 and only one answer is in the fifties, you are done.
Check the last digit. The wrong answers are frequently just one, two or three away from the right one, or exactly ten away. For an addition, adding the final digits tells you how the answer must end.
Do not guess. The freeze is long, and a wrong tap gives your opponent a free run at the point.
Know your tables. The multiplication questions are where most points are won, because someone who knows them answers instantly.
It works well between an adult and a child, since quick recall often beats experience. As two-player HTML5 games go, it is one of the few that counts as homework.