Mom bought 5 bags of washing powder, 2 kilograms each, and 7 kilograms were used up. How many kilograms are left?
妈妈买来5袋洗衣粉，每袋2千克，用去了7千克，还剩多少千克？
<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<gadget id="calculator">10 - 7</gadget>
<output>3</output>

<result>3</result>