John has 3 bedroom doors and two outside doors to replace.  The outside doors cost $20 each to replace and the bedroom doors are half that cost.  How much does he pay in total?
The outside doors cost 2*$20=$
<gadget id="calculator">2*20</gadget>
<output>40</output>
40.
Each indoor door cost $20/2=$
<gadget id="calculator">20/2</gadget>
<output>10</output>
10.
So all the indoor doors cost $10*3=$
<gadget id="calculator">10*3</gadget>
<output>30</output>
30.
That means the total cost is $40+$30=$
<gadget id="calculator">40+30</gadget>
<output>70</output>
70.

<result>70</result>