64*2-□=6.4*10, what is the number in □.
64*2-□=6.4*10，□中的数是多少．
<gadget id="calculator">6.4 * 10 * 2</gadget>
<output>128</output>

<gadget id="calculator">6.4 * 10</gadget>
<output>64</output>

<gadget id="calculator">128 - 64</gadget>
<output>64</output>

<result>64</result>