Given:
47% of 89
Exact solution is : 0.47 * 89 = 41.83
Estimates: you round the number to the nearest tens.
47% can be 50% ; 89 can be 90
0.50 * 90 = 45
50% is the same as 1/2
1/2 * 90 = 45
90/2 is also applicable to estimate for the above figure. 90/2 = 45
