Tony has a bucket that holds 2 pounds of sand. He has a sandbox out back that is two feet deep, four feet wide, and 5 feet long. A cubic foot of sand weighs 3 pounds. Because it's hot outside, he wants to make sure he stays hydrated, so every 4 trips he takes he drinks 3 ounces of bottled water. A 15 ounce bottle of water costs $2. He has $10 with him. How much change will he have after he buys all the water he needs?
The sandbox is 40 cubic feet because 2 x 4 x 5 = 
<gadget id="calculator">2*4*5</gadget>
<output>40</output>
40.
He needs 120 pounds of sand because 40 x 3 = 
<gadget id="calculator">40*3</gadget>
<output>120</output>
120.
He will take 60 trips because 120 / 2 = 
<gadget id="calculator">120/2</gadget>
<output>60</output>
60.
He will need to drink water 15 times because 60 / 4 = 
<gadget id="calculator">60/4</gadget>
<output>15</output>
15.
He will drink 45 ounces of water because 15 x 3 = 
<gadget id="calculator">15*3</gadget>
<output>45</output>
45.
He will need 3 bottles of water because 45 / 15 = 
<gadget id="calculator">45/15</gadget>
<output>3</output>
3.
He will spend $6 on water because 3 x 2 = 
<gadget id="calculator">3*2</gadget>
<output>6</output>
6.
He will have $4 in change because 10 - 6 = 
<gadget id="calculator">10-6</gadget>
<output>4</output>
4.

<result>4</result>