The rice is 2.2 yuan per kilogram. My mother bought 13.5 kilograms and paid 100 yuan to the aunt in the grain and oil store. How much should I get back?
大米每千克2.2元，妈妈买了13.5千克，付给粮油店阿姨100元，应找回多少元？
<gadget id="calculator">13.5 * 2.2</gadget>
<output>29.7</output>

<gadget id="calculator">100 - 29.7</gadget>
<output>70.3</output>

<result>70.3</result>