Written February 18, 2018 Suppose you need to calculate \(101^2\) but you don't have a calculator handy. How would you estimate it? \(100^2\) is pretty easy: \(100 * 100 = 10000\). But \(101^2\) seems tougher. Or suppose you had to estimate \(4.1^2\). How would you do it? What about \(7.1^2\)? In all these cases, you know the square of a number that is pretty close (\(100^2\), \(4^2\), \(7^2\)). C