My mother buys 1 bag of rice and 2 kg of sugar in the supermarket for a total of 81 yuan. It is known that the price of this bag of rice is 75 yuan, how much is it per kilogram of white sugar?
妈妈在超市买1袋大米和2千克白糖一共用去81元．已知这袋大米的价钱是75元，每千克白糖多少元？
<gadget id="calculator">81 - 75</gadget>
<output>6</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<result>3</result>