Mom originally had 500 yuan and bought two barrels of oil with a unit price of 128 yuan. How much money is left?
妈妈原来有500元钱，买了两桶单价是128元的油，还剩多少元？
<gadget id="calculator">128 * 2</gadget>
<output>256</output>

<gadget id="calculator">500 - 256</gadget>
<output>244</output>

<result>244</result>