Pre-Algebra

Scientific notation makes it easy to work with very large and very small numbers. If the exponent is positive, we're dealing with a very large number.

If the exponent is negative, we're dealing with a very small number.

There's no rule about how many decimal places you need in scientific notation. For example, 2.3 × 10⁴ or 2.31 × 10⁴ or 2.313 × 10⁴. It's very common to round to the tenth place. You can have as many as you want but if you use too many it kind of takes away the point of using scientific notation in the first place.