Multiply a number by 4, add 84, subtract 20, and divide by 2 to get 100. What is this number?
把一个数乘以4，加上84，再减去20，最后除以2，这时得100，那么这个数是多少？
<gadget id="calculator">100 * 2</gadget>
<output>200</output>

<gadget id="calculator">20 - 84</gadget>
<output>-64</output>

<gadget id="calculator">200 + (-64)</gadget>
<output>136</output>

<gadget id="calculator">136 / 4</gadget>
<output>34</output>

<result>34</result>