Mr. carson wants to give three pencils to each of his students. there are 26 students in mr. carsons class. boxes of pencils each contain a dozen pencils. how many boxes of pencils will mr. carson need? my son needs to give a written explanation on how he got the answer.

Since there are 26 students in Mr. Carson's class, and each kid gets 3 pencils, that means we will multiply 26 and 3, in which we get 78. Now, since boxes of pencils only contain a dozen, which is 12 pencils, we will divide 78 by twelve, in which we get 6.5 boxes. You can't buy half a box, so he will need 7 boxes, since having 6 boxes means that you don't have enough pencils.

Hope this helps!

First of all you have really good information for this question:
Mr Carson=3 pencils per student.
26 students=Mr Carson
Boxes=12 pencils.
So, what you need to do, is to multiply 26 students by 3 pencils and then divide the total by 12, which is 6.5. BUT, You can't buy half a box. So, you round  6.5 to the nearest tenth, which is 7. Mr Carson can buy 7 boxes
Hope this helps