Ernest bought 50 meters of wire and cut it into 5 equal parts. He then used 3 parts of the wire. How many meters of wire is not used?
Each part of the wire is 50/5 = 
<gadget id="calculator">50/5</gadget>
<output>10</output>
10 meters long.
Ernest used 3 parts, then he used 10 x 3 = 
<gadget id="calculator">3*10</gadget>
<output>30</output>
30 meters of the wire.
Therefore, 50 - 30 = 
<gadget id="calculator">50-30</gadget>
<output>20</output>
20 meters of wire is not used.

<result>20</result>