Powers of ten notation

If you are familiar with powers of ten or exponential notation for very large or very small numbers you can skip this section.

In everyday life we have hardly any occasion to use really big numbers. For quite a lot of transactions the ten fingers are enough. We speak of having one house, two cars, three children, of buying ten apples, or of earning some thousands of pounds or dollars a year. All of these numbers can be written with a few digits. On the other hand, financial newspapers or a finance Minister deal in millions and billions of pounds or dollars.

Science extends far beyond the everyday domain of our senses, and doesn't shrink from large numbers. There is no practical word, at once precise and in general use, to describe the number of synapses in the brain, the number of stars in our galaxy or the number of molecules in a litre of water. To express such quantities we use powers of ten. They have their origin in mathematics, but you don't need to know too much in order to understand their principle.

Quite simply: ten to the power of one is ten or 10; the second power is ten multiplied by itself twice, that is a hundred or 100.