Mom bought 15 kilograms of rice at 2.30 yuan per kilogram, and 15 kilograms of flour at 2.70 yuan per kilogram. Mom paid 100 yuan, how much should I get back?
妈妈买了15千克大米，每千克2.30元，又买了15千克面粉，每千克2.70元．妈妈付了100元，应该找回多少钱？
<gadget id="calculator">15 * 2.3</gadget>
<output>34.5</output>

<gadget id="calculator">15 * 2.7</gadget>
<output>40.5</output>

<gadget id="calculator">34.5 + 40.5</gadget>
<output>75</output>

<gadget id="calculator">100 - 75</gadget>
<output>25</output>

<result>25</result>