2.4 yuan per kilogram of flour, 3.2 yuan per kilogram of rice. If you buy 15 kilograms of flour and 15 kilograms of rice each, and pay 100 yuan, how much should you get back?
每千克面粉2.4元，每千克大米3.2元．买面粉和大米各15千克，付出100元，应找回多少元？
<gadget id="calculator">2.4 + 3.2</gadget>
<output>5.6</output>

<gadget id="calculator">5.6 * 15</gadget>
<output>84</output>

<gadget id="calculator">100 - 84</gadget>
<output>16</output>

<result>16</result>