Djibo is 17 years old. Five years ago Djibo added his age with his sister's age and the sum was 35. How many years old is Djibo's sister today?
Age 5 years ago: 17 - 5 = 
<gadget id="calculator">17-5</gadget>
<output>12</output>
12.
Sister's age 5 years ago: 35 - 12 = 
<gadget id="calculator">35-12</gadget>
<output>23</output>
23.
Sister's age today: 23 + 5 = 
<gadget id="calculator">23+5</gadget>
<output>28</output>
28 years.
Djibo's sister is 28 years old today.

<result>28</result>