His mother will give Xiao Ming the same amount of pocket money every month. Xiao Ming’s pocket money for a year can buy a set of "One Hundred Thousand Whys", which is 100 yuan more. After 7 months, he used his pocket money to buy a set of "One Hundred Thousand Whys". "Why", there is still 20 yuan left. May I ask how much is a set of "One Hundred Thousand Whys"?
妈妈每个月都会给小明同样多的零用钱，小明一年的零用钱能买一套《十万个为什么》还多100元，经过7个月他就用零用钱买了一套《十万个为什么》，还剩下20元．请问一套《十万个为什么》多少钱？
<gadget id="calculator">100 - 20</gadget>
<output>80</output>

<gadget id="calculator">12 - 7</gadget>
<output>5</output>

<gadget id="calculator">80 / 5</gadget>
<output>16</output>

<gadget id="calculator">16 * 7</gadget>
<output>112</output>

<gadget id="calculator">112 - 20</gadget>
<output>92</output>

<result>92</result>