Compute 189 × 37 in your head

Question

Solve in your head, no paper. What is 189 	imes 37? Aim: under 20 seconds.

Accepted Answer

Since 189 is just below 200, round it up and subtract the overshoot: 189 = 200 - 11. - 200 	imes 37 = 7400, free. - 11 	imes 37 = 407. 7400 - 407 = 6993. Even cleaner, 189 = 190 - 1: 190 	imes 37 = 7030, minus 37 = 6993. Either way, "seventy-four hundred... sixty-nine ninety-three." Takeaway. When a factor sits just under a round number, round up and subtract rather than splitting downward: 189 	imes 37 = 200 	imes 37 - 11 	imes 37. The correction (11 	imes 37) is a small 2 	imes 2 multiply, the easy leftover you always aim to reach.

Compute 189 × 37 in your head

Your answer

Discussion

Learn the concepts

Related questions