About half of 250 cyclists finished before noon. Estimate first, then choose the exact value of 48% of 250.

Explication

The exact calculation is 0.48 x 250 = 120, which is close to the estimate of half of 250, or 125. The value 202 subtracts 48 as a fixed amount instead of taking 48% of the base, while 12 comes from a decimal-place slip.