How to set up problem?

Question

Mr Honeycutt has made a deal with the class. He said for every homework assignment that each student completes perfectly, he will allow that student to skip the next three assignments for credit. If he plans 31 assignments, how many would a student have to complete perfectly to have the least amount of homework?

Answer 1

Hi Whitney.  I did this by writing the numbers in order and circling number 1, and then each 4th number.  So, I got 1, 5, 9, 13, 17, 21, 25, and 29.  that's eight assignments

 

I think you can also look at it like this:

 

31 assignments; do the first one perfectly, 30 are left:

 

30/4 = 7 with two left over.  So, 1 + 7 = 8