Round - GCSE Maths Definition

In mathematics, rounding a number involves writing a number to a degree of accuracy that is appropriate to the context.

For example,

• for the attendance at a football match, there is no need for the public to know there were exactly 78 254 people; rounding to the nearest 1000. 78 000 would be fine to give a good, general idea, of how many people were there
  (do be aware, that for someone working for the football club, and accounting income, the exact number 78 254 may be very important!)

• if calculating a distance, say, a golf ball travels in the air once hit, is 245.642 345 metres, there is no need to use all the decimal places - they are going into fractions of millimetres, which is meaningless in the sport of golf. One decimal place (tenth of a metre) would be sufficient, and we would say the golf ball travelled 245.6 metres in the air.

Numbers are rounded to either a stated number of decimal places, or a stated number of significant figures. To round a number, we find the last digit that will remain, and consider the following digit to determine whether to round up, or down. When the following digit is 0, 1, 2, 3 or 4, we round down (and the last digit will not change); when that following digit is 5, 6, 7, 8 or 9, we round up (and the last digit will increase by 1).

Rounding numbers make them easier to read and interpret, as well as being more meaningful in the context of a question.