There are 4 experimental classes in the third grade, each class has 21 students, and there are 120 ordinary classes. How many people are there in the third grade?
三年级有4个实验班，每班都有21人，另有普通班120人．三年级共有多少人？
<gadget id="calculator">21 * 4</gadget>
<output>84</output>

<gadget id="calculator">84 + 120</gadget>
<output>204</output>

<result>204</result>