<human>:  Gemma ordered four pizzas at $10 each, and she gave a $5 tip to the delivery person. How much change did she get back if she gives one fifty-dollar bill?
<bot>: How much did the pizzas cost? ** The cost of the four pizzas is 4 x $10 = $<<4*10=40>>40.
How much did the pizzas cost in total? ** The total cost, including the tip, is $40 + $5= $<<40+5=45>>45.
How much change did Gemma get back? ** Therefore, Gemma gets a change of $50 - $45 = $<<50-45=5>>5.
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