question: David has $12.48 and wants to buy 16 bolts from a bin at the hardware store. Each bolt costs $0.03. How much money does David have left after paying for the bolts?
answer: David paid 16 * 0.03 = $<<16*0.03=0.48>>0.48 for the bolts.
  David has $12.48 - $0.48 = $12 left.
  #### 12