The rules for adding and subtracting signed decimals are almost the same as the rules for adding and subtracting integers. When dealing with decimals, you need to be especially aware that your decimal points are lined up so that you do not accidentally add or subtract in the wrong place.
32 students would be on the trip. What I did to solve it was a proportion. 8students/ 3 chaperones= x students/12 chaperones. 8*12= 96 and 96/3=32. Therefore 32 students were on the trip.
