Fast multiplication

How this works

Read the question and type the answer. Press Enter to check it. Press Enter again for the next question.

Every question has one method, written out step by step. In the ten question round it appears under each answer. In the sprint it waits in the review at the end, so the clock is not spent reading.

Classic: Level 1 is two digit times one digit: split the two digit number, multiply the parts, add. Level 2 is the shortcuts: multiply by 11, by 5, by 25 and by 50, squares ending in 5, and doubling and halving. Level 3 is two digit pairs near a round number, both just below 100 or both just above 50. Level 4 is any two digit pair, split one number or use the difference of squares. Extended: Complementary units and signed offsets around 100 and 1,000.

The ten question round has no countdown. The sprint runs for three minutes, and that clock stops while the tab is in the background, so a round you walk away from is not counted against you.

Your score is how many answers were right. Finish the ten questions, or let the sprint clock run out, to save the round in this browser. Ending early saves nothing. The statistics page compares the share of answers that were right, so read a sprint score next to the number of questions it had. It is arithmetic practice, not a measure of ability.

Type digits. Enter checks your answer. Enter again moves to the next question. Escape ends the round, and so does the End button.