A bottle contains 128ml of salt solution. Three students are out 0.75ml, 1.2ml, and 0.022ml what is the volume that remains?

Question

 This question isn't testing my ability to subtract , but i'm not sure what to do.

Answer 1

Is it possible that this question deals with significant figures.  In that case, we simply do the subtraction, and then round to the lowest decimal place of the least precise measurement.  This would give:

 

128 - 0.75 - 1.2 - 0.022 = 126.028

 

round to the least precise decimal place (the ones place)

 

Answer: 126 mL