conversations.from: human
conversations.value: Mark buys a loaf of bread for $4.20 and some cheese for $2.05. He gives the cashier $7.00. If the cashier only has 1 quarter and 1 dime in his till, plus a bunch of nickels, how many nickels does Mark get in his change?
  Can you solve this problem?
conversations.from: assistant
conversations.value: First subtract the cost of Mark's groceries from the amount he gives the cashier to find how much he gets in change: $7.00 - $4.20 - $2.05 = $0.75
  Then subtract the value of a quarter in cents (25) and the value of a dime in cents (10) from the change amount to find how much Mark gets paid in nickels: $0.75 - $0.25 - $0.10 = $0.40
  Now divide the amount Mark gets in nickels by the value per nickel in cents (5) to find how many nickels Mark gets: $0.40 / $0.05/nickel = 8 nickels