Jeff is 10 years older than his younger sister, Martha. Martha, on the other hand, is 4 years younger than her boyfriend, Mike. If Mike is 24 years old, how old is Jeff?
Martha is 24 - 4 = 
<gadget id="calculator">24-4</gadget>
<output>20</output>
20 years old.
Jeff is 20 + 10 =
<gadget id="calculator">20+10</gadget>
<output>30</output>
30 years old.

<result>30</result>