Add 8 to a number, multiply by 7, subtract 7, divide by 7, and the result is still 7. Guess what this number is.
一个数加上8，乘以7，减去7，除以7，结果还是7，你猜猜这个数是多少．
<gadget id="calculator">7 * 7</gadget>
<output>49</output>

<gadget id="calculator">49 + 7</gadget>
<output>56</output>

<gadget id="calculator">56 / 7</gadget>
<output>8</output>

<gadget id="calculator">8 - 8</gadget>
<output>0</output>

<result>0</result>