1. The problem statement, all variables and given/known data If I measure A=50, with a minimum value of 48, and a maximum value of 51, and measure B=100, with a minimum value of 92, and a maximum value of 115, and I add the two (C=A+B) together, what is the resulting minimum and maximum value of C? 2. Relevant equations If A and B had uncertainties A=(50+/-2) and B=(100+/-10), rather than the lower and upper uncertainties differing, then the uncertainty in C would be: SQRT((2^2)+(10^2)) 3. The attempt at a solution Can I use the above expression for the lower uncertainties, and then again on the upper uncertainties, to individually calculate the upper and lower C values? So we'd get: C_minimum = SQRT((2^2)+(8^2)) = SQRT(4+64)=SQRT(68)=8.246 =:= 8 and C_maximum = SQRT((1^2)+(15^2))=SQRT(1+225)=SQRT(226)=15.03 =:= 15 so C=150 with a minimum value of 142 and a maximum value of 165. Does this seem correct?