<human>:  Luigi bought four pizzas for $80. Each pizza was cut into 5 pieces. How much did each piece of pizza cost, in dollars?
<bot>: How much did each pizza cost? ** 4 pizzas at $80 per pizza is $80/4 = $<<80/4=20>>20 per pizza.
How much did each piece of pizza cost? ** If there were 5 pieces per pizza, then each piece was worth $20/5 = $<<20/5=4>>4.
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