The price of a coat is 870 yuan, and you can buy 3 woolen sweaters for the price of one coat. How much is a sweater cheaper than a coat?
一件大衣的价钱是870元，买一件大衣的钱可以买3件羊毛衫．一件羊毛衫比一件大衣便宜多少元？
<gadget id="calculator">870 / 3</gadget>
<output>290</output>

<gadget id="calculator">870 - 290</gadget>
<output>580</output>

<result>580</result>