Lingling has some money, she used (2/5) for the first time, and got another 240 yuan, and used (1/3) for the second time, leaving 720 yuan, how much was she used for the first time?
玲玲有一些钱，第一次用去(2/5)，又得到240元，第二次用去这时的(1/3)，还剩720元，问第一次用去多少元？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">720 / (2/3)</gadget>
<output>1_080</output>

<gadget id="calculator">1_080 - 240</gadget>
<output>840</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">840 / (3/5)</gadget>
<output>1_400</output>

<gadget id="calculator">1_400 * (2/5)</gadget>
<output>560</output>

<result>560</result>