James earns $10 per week as an allowance. After saving all his money for four weeks, he spends half of it on a new video game. He then spends a quarter of what is left to buy a new book. How much money does he have left?
He starts out with $10 * 4 = $
<gadget id="calculator">10*4</gadget>
<output>40</output>
40.
James spend $40 / 2 = $
<gadget id="calculator">40/2</gadget>
<output>20</output>
20 on the video game.
After buying the game, he has $40 - $20 = $
<gadget id="calculator">40-20</gadget>
<output>20</output>
20 left.
He spent $20 / 4 = $
<gadget id="calculator">20/4</gadget>
<output>5</output>
5 on the book.
He has $20 - $5 = $
<gadget id="calculator">20-5</gadget>
<output>15</output>
15 left.

<result>15</result>