Given f = u.v/u+v

U= 8.8, v= 6.2 correct to 1 decimal place.

Find the upper and lower bound of F

Upper boundF= 8.85x6.25/8.75+6.15

lower bound F = 8.75x6.15/ 8.85+6.25

Second part of the question is find a mistake in the problem, I can't figure it out what it is?