Will buys 15 oranges. When he gets home, he asks his 2 sons to wash as many oranges as they are years old. The oldest son is 8 years old, the youngest is half as old as the oldest. How many oranges are left unwashed?
The older son washes 8 oranges, so the younger son washes 8 / 2 = 
<gadget id="calculator">8/2</gadget>
<output>4</output>
4 oranges.
Together they wash 8 oranges + 4 oranges =
<gadget id="calculator">8+4</gadget>
<output>12</output>
12 oranges.
There are 15 oranges - 12 oranges = 
<gadget id="calculator">15-12</gadget>
<output>3</output>
3 oranges left unwashed.

<result>3</result>