What are the 3 rules for writing numbers in standard form?

Firstly, convert the number to a decimal with only one number before the decimal point by dividing by 10 as many times as needed e.g.

2345 ÷ 10 = 234.5 ÷ 10 = 23.45 ÷ 10 = 2.345

We divided it by 10 three times to get our decimal.

Now we can write our standard form:

2.345 x 10 to the power of 3 (because we must multiply the decimal by 10 three times)

If we have a very small number, we multiply it to get a standard decimal e.g.

0.00071 x 10 = 0.0071 x 10 = 0.071 x 10 = 0.71 x 10 = 7.1

We multiplied by 10 four times.

When it comes to writing the number in standard form, we always use multiplication, so when we have multiplied to reach the decimal, we have to multiply it by a negative number:

7.1 x -10 to the power of 4

If written in the form M x 10^n, the 3 rules are:

1) YM must be between 1 and 10

2) standard form uses base 10, I.e. 10 to the power of something (n)

3) n must be a whole number.