James decides to buy birthday candles for his 2 sons.  One of them is 12 and the other is 4 years younger.  A pack of 5 candles costs $3.  How much does James spend on candles?
His younger son is 12-4=
<gadget id="calculator">12-4</gadget>
<output>8</output>
8 years old.
So he needs 12+8=
<gadget id="calculator">12+8</gadget>
<output>20</output>
20 candles.
That means he needs 20/5=
<gadget id="calculator">20/5</gadget>
<output>4</output>
4 packs of candles.
The total cost of those is 4*3=$
<gadget id="calculator">4*3</gadget>
<output>12</output>
12.

<result>12</result>