arithmetic

Are you bored with 1 to 12? Then have a look at these mathematical clock faces!

Need to find the least common multiple or greatest common divisor of two numbers? A billiard table of the right proportions holds the answers!

If you like playing with numbers, then this one's for you!

There are some amazing patterns hiding within simple arithmetic.

Eleven makes multiplication easy.

How to write down unimaginably large numbers using just a few symbols.

Why do we add fractions the way we do? A very close look at addition reveals the answer — and it also works for negative numbers.

The Indian way of adding fractions makes things easier (with musical explanation).

How would you go about adding up all the integers from 1 to 100? Tap them into a calculator? Write a little computer code? Or look up the general formula for summing integers?

The number 1 can be written as a sum of unit fractions, that is fractions with 1 in the numerator. But how long can we make such a sum?