149 minus 7 times a number, the difference is 58, find this number.
149减去一个数的7倍，差是58，求这个数．
<gadget id="calculator">149 - 58</gadget>
<output>91</output>

<gadget id="calculator">91 / 7</gadget>
<output>13</output>

<result>13</result>