Question

Dr. Gallo's waiting room has a total of 18 magazines, including 3 fashion magazines. There are 5 more cooking magazines than there are decorating magazines. How many decorating magazines are there? You can use cubes to act out the problem.

Answer 1

f=3
c=d+5
so,
f+c+d=18
3+(d+5)+d=18
2d+8=18
2d=10
d=5

5 decorating magazines

Answer 2

if you were using cubes, you'd start out with 3 cubes for the fashion.

Then gather cubes together for the others, with 5 extras for the cooking.

Start adding in cubes until you get a total of 18:

f d c
3 1 6
3 2 7
3 3 8
3 4 9
3 5 10 <---------!!