400
There are 4 classes of 3rd graders at Altama Elementary. They are planning a field trip to the zoo. Mrs. Crutchfield has 19 students, Mrs. Kroupa has 23 students, Mrs. Knighten has 22 students, and Mr. Cook has 24 students. They are trying to figure out how many buses they need. If they can only put 33 students on each bus, how many buses will they need?
3 because there are 78 students in all and when you subtract 33 from 78 two times you still have 12 students that need to get on a bus.