Compute 88 × 25 in your head

Question

Solve in your head. What is 88 	imes 25? Aim: under 10 seconds.

Accepted Answer

Route 1, treat 	imes 25 as 	imes 100 \div 4: 88 	imes 25 = \frac{88 	imes 100}{4} = \frac{8800}{4} = 2200. Route 2, split the 25: 88 	imes 25 = 88 	imes 20 + 88 	imes 5 = 1760 + 440 = 2200. Route 1 is cleaner because 88 is divisible by 4, so 8800 / 4 = 2200 falls out in one step. When the other factor is not a nice multiple of 4, Route 2 (or first halving twice) is the safer path. Takeaway. 	imes 25 means "append two zeros, then quarter it," just as 	imes 50 is "halve after appending two zeros." Spotting the hidden factor of 100 turns an awkward product into a one-step division.

Compute 88 × 25 in your head

Your answer

More Mental Math questions