I have purchased 5 blue apples at the store. Suppose my neighbor gives me twice as many yellow apples as I have blue ones, and then I give my son 1/5 of the total number of apples; how many apples do I have now?
The number of blue apples is 5, and if you receive twice as many yellow apples as the number of blue apples, there will be 5*2 = 
<gadget id="calculator">5*2</gadget>
<output>10</output>
10 yellow apples.
After receiving the yellow apples, you now have 10 yellow apples+5 blue apples = 
<gadget id="calculator">10+5</gadget>
<output>15</output>
15 apples.
When you give 1/5 of the total number of apples to the son, you part with 1/5*15 = 
<gadget id="calculator">1/5*15</gadget>
<output>3</output>
3 apples.
The total number of apples remaining is 15-3 = 
<gadget id="calculator">15-3</gadget>
<output>12</output>
12 apples.

<result>12</result>