Question

By first rounding both numbers to 1
significant figure, estimate the answer to
12 x 478

Answer 1

Explanation:

Rounding to 1 sig fig:

12 becomes 10

478 becomes 500 (that hurts)

Multiply

10 x 500 = 5000

[Actual value of 12 x 478 is 5736. The reason the estimated value is lower is due to the fact that going from 12 to 10 was a reduction of 17%, while going from 478 to 500 was an increase of only 5%]