4 ms·
For C to F you can often simplify the mental math by doing the multiply by doubling then taking off 10%. E.g., to convert 31℃ to ℉: 31 x 2 = 62. Subtract 6.2 =
by tzs 9mo ago
For C to F you can often simplify the mental math by doing the multiply by doubling then taking off 10%.
E.g., to convert 31℃ to ℉: 31 x 2 = 62. Subtract 6.2 = 55.8. Add 32 = 87.8℉.
If you want to round the result to the nearest integer the subtract 10% step is a convenient place: 31 x 2 = 62. Subtract 6 (rounded 6.2) = 56. Add 32 = 88℉.
- SECProto 9mo agoYes, doubling then subtracting 10% of the resultant works because that is the same as multiplying by 1.8 :) When going the other way and dividing, I similarly find it mentally easier to multiply by 10/18 (rather than just divide by 1.8)