Mr. Lin has to give art classes to 4 classes every day, and the number of students in each class is between 32-36. About how many students Mr. Lin has to teach every day.
林老师每天要给4个班上美术课，每个班学生人数都在32-36之间，林老师每天大约要给多少学生上课．
<gadget id="calculator">30 * 4</gadget>
<output>120</output>

<gadget id="calculator">40 * 4</gadget>
<output>160</output>

<gadget id="calculator">120 - 160</gadget>
<output>-40</output>

<result>-40</result>