GCSE(F) GCSE(H)

As well as very large numbers, standard form also deals with very small numbers:

4.56 x 10^{-3} is 4.56 ÷ 1000 = 0.00456.

To turn a small number written in standard form into a normal number, divide the number by the power of 10:

8.45 x 10^{-4}

= 8.45 ÷ 10 000

= 0.000845 (note that the 8 is the 4^{th} digit after the decimal point

To turn a small number into standard form, identify the number that will be between 1 and 10. For example, 0.00406:

4.06 is the number between 1 and 10

it needs to be divided by 1000

therefore 4.06 x 10^{-3}

1. A white blood cell has a diameter of 1.2 x 10^{-5}m. Write this as a normal number.

Answer: 0.000012m

1.2 x 10^{-5}

= 1.2 ÷ 100,000

= 0.000012

2. Write -0.056 in standard form.

Answer: -5.6 x 10^{-2}

-0.056

= -5.6 ÷ 100

= -5.6 x 10^{-2}

Our iOS app has over 1,000 questions to help you practice this and many other topics.

Available to download free on the App Store.

Available to download free on the App Store.