
Problem Solving Examples 121
Example 5.4 Finding Square Root with a Cheap Calculator
The final example in this chapter is to illustrate the use of divide and conquer strategy
in solving a problem. Suppose we have a cheap calculator that has only four basic arith-
metic functions: addition, subtraction, multiplication, and division. However, we need
to calculate the square root of a number greater than one, let us say N. We will now see
how we can find the square root of a number with such a cheap calculator.
Let us begin by first noting what we know about this problem in general. For example,
we know that if R is the square root of a number N,