question: Grayson recycles cans and bottles for money each week. An aluminum can is worth two cents and a plastic bottle is worth three cents. She drinks three aluminum cans of soda and five plastic bottles of water a week. How many cents does Grayson earn from recycling in a four-week month?
answer: Grayson earns 2 * 3 = <<2*3=6>>6 cents from soda cans a week.
  She earns 3 * 5 = <<3*5=15>>15 cents from water bottles a week.
  Thus, she earns 6 + 15 = <<6+15=21>>21 cents from recycling each week.
  In a four week month, she earns 21 * 4 = <<21*4=84>>84 cents from recycling.
  #### 84