Xiao Ming did a calculation problem. The original problem was to divide a number by 7 and add 72. Because of his carelessness, he turned division into multiplication and addition into subtraction. Coincidentally, the number was correct. The number of this problem was how many.
小明做一道计算题，原题是一个数除以7，再加上72，由于粗心，他把除以算成了乘，加算成了减，凑巧得数是对的，这道题的得数是多少．
<gadget id="calculator">72 - 0</gadget>
<output>72</output>

<gadget id="calculator">72 + 72</gadget>
<output>144</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">7 - (1/7)</gadget>
<output>48/7 = around 6.857143</output>

<gadget id="calculator">144 / (48/7)</gadget>
<output>21</output>

<gadget id="calculator">21 * 7</gadget>
<output>147</output>

<gadget id="calculator">147 - 72</gadget>
<output>75</output>

<result>75</result>