Multiply a number by 2, add 4, divide by 7, subtract 1, and get 1. What is the number?
一个数乘以2，加上4，再除以7，减去1，后得1，这个数是多少．
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">2 * 7</gadget>
<output>14</output>

<gadget id="calculator">14 - 4</gadget>
<output>10</output>

<gadget id="calculator">10 / 2</gadget>
<output>5</output>

<result>5</result>