# Who invented arithmetic?

Arithmetic is the science of numbers. It is concerned with the meanings of numbers, with their symbols, and with ways of working with them.

Nobody "invented" arithmetic. It developed to meet man's needs. At first it had to do with quantity, not with counting. Before people could count, they had a "number sense." For example, early man could tell when he had picked enough berries. A hunter could tell by looking that he had lost a spear.

But as time passed, men needed numbers and number names. Herders needed to keep track of their animals. Farmers needed to keep track of the seasons. So at some unknown time, long ago, the first numbers and number names were invented. These are counting numbers, which we also call whole numbers, or natural numbers.

Later, men needed to have numbers that were less than 1, and numbers between other numbers. So fractions were developed. Much later, still other kinds of numbers came into use. One kind was negative numbers, like -2 or -7.

The idea of negative numbers was very hard to discover. In ancient Greece, it was known that if you took 5 from 7 you had 2 left. But was it possible to take 7 from 5? The Greeks decided it was not.

Not until the 1500's did people begin to see that there could be a number that was less than nothing. For example, take 7 from 5 and you have 2 less than 0, or -2.

With counting as the basic process, man learned to add, subtract, multiply, and divide—the four basic operations in arithmetic.