100 bags of cement were shipped to the construction site. After one batch was used up, there were still 36 bags left. How many bags were used? (List the equations containing the unknown X, and then solve it)
工地运来100包水泥，用去了一批后，还剩下36包，用去了多少包？(列出含有未知数X的等式，再解答)
<gadget id="calculator">100 - 36</gadget>
<output>64</output>

<result>64</result>