Mary wants to bake 10 apple pies for a charity event. Each pie needs 8 apples and she already harvested 50 apples from the trees in her garden. How many more apples does she need to buy to make all 10 pies?
She needs 10*8=
<gadget id="calculator">10*8</gadget>
<output>80</output>
80 apples to make the pies.
So she has to buy 80-50=
<gadget id="calculator">80-50</gadget>
<output>30</output>
30 more apples.

<result>30</result>