Standard form, or standard index form, is a system of writing numbers which can be particularly useful for working with very large or very small numbers. It is based on using powers of 10 to express how big or small a number is. Standard form is written in the form of a×10n, where a is a number bigger than or equal to 1 and less than 10. n can be any positive or negative whole number. For example 1.2×103,3.14×10−5 The rules when writing a number in standard form is that first you write down a number between 1 and 10, then you write ×10 (to the power of a number). Thus the decimal point must be behind the first non-zero digit If you move the decimal point to the left, the power (number of times of movement) of 10 will be positive and if to the right, negative The first non-zero digit in 0.000344 is 3 , hence we have to move the decimal point (.) 4 times to the right before placing it behind the 3 . Since the movement is to the right, the power (4) of 10 is negative. ⇒0.000344=3.44×10−4 in standard form