Denise will be 25 years old in two years. Her sister, Diane, is 4 years younger. In how many years will Diane be 25 years old?
Denise is 25 - 2 = 
<gadget id="calculator">25-2</gadget>
<output>23</output>
23 years old now.
So, Diane is 23 - 4 = 
<gadget id="calculator">23-4</gadget>
<output>19</output>
19 years old now.
Diane will be 25 years old in 25 - 19 = 
<gadget id="calculator">25-19</gadget>
<output>6</output>
6 years.

<result>6</result>