Kennan has 7 sheets of paper. he uses 2 1/2 sheets to make posters. he cuts the remaining paper in 6 equal rectangles to make cards each rectangle is 1/4 of sheet of paper. how many cards can he make?

Remaining paper
7 - 2 1/2 = 4 1/2

Equivalent Fraction:
4 1/2 = 9/2 = 18/4

if each piece is 1/4 of the sheets, 
18/4 ÷ 1/4 = 18/4 x 4/1 = 18

I am slightly not too sure what the remaining papers is cut into 6 equal rectangle will imply in this question. But looking at the answer, 18, then it is possible that he cuts 3 triangles out from each rectangle (which he will still get 18) which makes the answer possible.

Multiply 9 and 67. then multiply 3 with 67. lastly the answer that you got for 9x67 is to be subtracted by the answer you got for 3x67