Decimal & standard form
- Decimals are any numbers which include a decimal point, for example:
- 6.31
- 20.059
- 468.27
- The digits before the decimal point are whole numbers; the digits after the decimal point are parts of that whole number, e.g.
- 6.31 = the 6 in this number refers to 6 units; 3 in this number refers to 3 tenths
- 20.059 = the 2 in this number refers to two tens; the 9 refers to 9 hundredths
- 468.27 - the 4 in this number refers to 4 hundreds; the 2 in this number refers to 2 tenths
- Standard form is a way of dealing with very large (or very small) numbers without the process becoming too cumbersome and complex, e.g.
- 10 to the power of 2 = 100, which is written as 102 (i.e. it refers to 10 x 10)
- 835,000,000,000 = 8.35 × 1011 in standard form (835 must be reduced to a number between 1 and 10 and then 10 ‘to the power of’ is added to express the number)
- Small numbers can also be written in standard form, however, the index (the ‘to the power of’ number) must be negative, e.g. 0.000000000000761 is written as 7.61 × 10-13
Exam Tip
You can read more about standard form in our maths pages here.