There are some candies between 20 and 30 yuan, which are distributed to 7 students on average, and there are 3 yuan left. How many pieces of these candies are there?
有一些糖在20～30块之间，平均分给7个同学，还剩下3块，这些糖有多少块．
<gadget id="calculator">3 * 7</gadget>
<output>21</output>

<gadget id="calculator">21 + 3</gadget>
<output>24</output>

<result>24</result>