Science uses lots of numbers describing things like distance and mass. The sun is big enough to hold 1.3 million earth-sized planets; light travels 650,000,000 miles per hour; a wave of yellow light entering your eye is .575x10^-9 meters long. Our preferred system of measurement is the metric system of meters and grams: a meter is 39.37 inches, and 28.35 grams make one ounce. (It's a better, more earth-based system, so just as well learn to use it and love it!) 

When numbers get very big (or small, we use scientific notation, based on powers of ten. Here's one now:

The cyan 4.38 is called the coefficient. The orange x means 'times'. The yellow 10 is the base, and the green 30 is the exponent . . . so the mass of the Sun can be read, Four point three eight times ten to the 30th. The number 1.3 million can be written

Our familiar number system is called base 10 (Extra credit: Why do you suppose we count in tens instead of sevens or twelves?) Other bases exist, theoretically any number – best if small – can define a base, and scientists adopt any convenient baseif it simplifies categorization and data handling. (Computers are everywhere!)