Estimation

What is Estimation?

Replacing the numbers in a calculation with nearby values that are easy to handle mentally, usually rounded to one significant figure, so that the size of the true answer is known before the calculation is performed. An estimate is a test of reasonableness, not a substitute for the accurate answer, and it is what makes a keying error or a misplaced decimal point visible.

This definition is part of the Number chapter in Cambridge O Level Mathematics (Syllabus D).

Concepts related to Estimation

• significant figures
• decimal places
• order of magnitude
• reasonableness check