human
Calvin buys a pack of chips, for $0.50, from the vending machine at lunch, 5 days a week. After 4 weeks, how much money has Calvin spent on chips?
assistant
How much do the chips cost? ** The chips cost $0.50 a bag and he buys them 5 days a week so that's .50*5 = $<<0.50*5=2.50>>2.50 a week
How much money does Calvin spend on chips? ** If he spends $2.50 on chips a week then over 4 weeks he will spend 2.50*4 = $<<2.50*4=10.00>>10.00 on chips
#### 10