What do you estimate 40.7 to?

Answer 1

Depends upon the situation I'm using the estimation and the other values in the estimation.

I may round it to 41 (nearest whole number - least likely), 40 (nearest 5 or 10 - most likely) or 50 (nearest 50 or in other words: half 100).

I may even round it to 42 or 45 - it's the potential factors of the estimations of all the numbers which will be a consideration when deciding the rounding to use for each of the numbers.