Flash Anzan (Flash Mental Math)Free, no sign-up

It's a mental math drill used in Japanese abacus (soroban) schools. Numbers appear for an instant one at a time, you add them up in your head, and you give the total at the end. The trick is to add each number the moment you see it, not to memorize them.

Level 1 is three 1-digit numbers, one per second. Each level adds more numbers and speeds up; numbers become 2 digits from level 6 and 3 digits from level 14. A correct total takes you to the next level; a wrong one ends the run.

Once all the numbers have been shown, an answer box appears. Enter the total with the keypad or number keys and press Enter (or Answer).

By the number of levels cleared, most first; ties go to the faster time. You only need a nickname, and you can submit up to 30 times a day. The server checks your list of answers.