Standard form

We have seen that the earth is around 10⁴ kilometres

We can also write the size of the earth in scientific notation which is also called standard form It is the way numbers are often written in science.

Standard form is the standard way to write very small or very large numbers.

When numbers are written in standard form they are written in the following way:

A x 10ⁿ

Here A stands for a number greater than or equal to 1 and less than 10 ()

n stands for an integer. For numbers less than 1, n is negative.

If we were to write 10⁴ in standard form, we would write 1 x 10⁴

It should be clear that these are the same number 1 x 10⁴ = 10⁴

The size of the earth to 2 sig figs is 13000 km

In standard form 13000 is 1.3 x 10⁴

The size of the earth to 3 sig figs is 12700 km

This is 1.27 x 10⁴ km

To 4 sig figs it is 1.274 x 10⁴ km

To 5 sig figs it is 1.2742 x 10⁴ km

The sun is 1.39 x 10⁶ km to 3 sig figs.