Nate starts his camping trip with 70 matches. He drops 10 in a creek and his dog eats twice as many. How many matches does he have left?
First find the number of matches the dog eats: 10 matches * 2 = 
<gadget id="calculator">10*2</gadget>
<output>20</output>
20 matches.
Then subtract all the lost matches from the starting number to find the final number: 70 matches - 10 matches - 20 matches = 
<gadget id="calculator">70-10-20</gadget>
<output>40</output>
40 matches.

<result>40</result>