Xiaodong wrote in his diary: On Sunday, our family brought 10,000 yuan to the Fashion Electric City to buy electrical appliances. Dad bought me an MP3 player with an original price of 600 yuan and now a 30% discount for me, and bought a new mobile phone for my mother. The price of my MP3 player is only 1/3 of the price of my mother’s mobile phone. Bought a laptop computer for himself with 6000 yuan. Today we are all very happy, I figured out today's expenses, my mother praised me: "It's really good that you can apply the knowledge you have learned in your life!" I smiled proudly, classmates, Xiaodong's classmate What math problems did you find in the math diary? Please record three and answer them.
小东在日记中写道：星期天，我们全家带了10000元到时尚电器城购买电器．爸爸买了一个原价600元现在打七折的MP3播放机送给我，又买了一部新款手机送给妈妈，我的MP3播放器的价钱只是妈妈手机价钱的(1/3)，爸爸还用6000元买了一台手提电脑送给他自己．今天我们都非常高兴，我算出了今天的花销情况，妈妈夸奖我："你能把学到的知识运用到生活中，真不错呀！"我自豪地笑了，同学们，从小东同学的数学日记中，你发现了哪些数学问题？请记录下三个，并解答出来．
<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">600 * (7/10)</gadget>
<output>420</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">420 / (1/3)</gadget>
<output>1_260</output>

<gadget id="calculator">10_000 - 420 - 1_260 - 6_000</gadget>
<output>2_320</output>

<result>2_320</result>