approximation & estimation

An approximation is a value that is nearly but not the exact answer.

eg 2.9 ✕  5 is approximately equal to 15 (as 3 ✕ 5 = 15)

We use a squiggly equal sign as the approximation symbol (some people use just one squiggly line).

An estimation or to make an estimate is to make an approximation or 'good guess' to a problem.

eg Estimate the height of an adult male

eg Estimate how many grams of raspberries are needed for Christmas Day.