Mingming found an interesting phenomenon when he was shopping. Every time he made a payment, the amount of money in his wallet was exactly 5 times the amount he paid. After he checked out three times, there was still 64 yuan left in his wallet. How many dollars did he have in his wallet before he started shopping?
明明在购物时发现一个有趣的现象，他每次付款时钱包内的钱数正好是所付金额的5倍．他结帐三次后结果钱包内还剩下64元．在开始购物前他钱包内有多少元．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">64 / 4</gadget>
<output>16</output>

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

<gadget id="calculator">80 / 4</gadget>
<output>20</output>

<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<gadget id="calculator">100 / 4</gadget>
<output>25</output>

<gadget id="calculator">25 * 5</gadget>
<output>125</output>

<result>125</result>