Grade 4 students line up in a solid square, and there are 10 people on each side of the outermost layer of the square, so how many people are there in the third layer from the outside to the inside?
四年级同学排成一个实心方阵，这个方阵最外层每边有10人，那么从外到里数第3层共有多少人．
<gadget id="calculator">10 - 4</gadget>
<output>6</output>

<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">24 - 4</gadget>
<output>20</output>

<result>20</result>