Both Li Hong and Zhang Hua are philatelists. There are 120 stamps in total. He gives Zhang Hua 15 stamps. Zhang Hua's stamps are equivalent to Li Hong's (2/3). How many original stamps does Li Hong have? (Solution of column equation)
李红和张华都是集邮爱好者，共有邮票120张，他给张华15张，张华的邮票就相当于李红的(2/3)．李红原有邮票多少张？(列方程解)
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">15 * (2/3)</gadget>
<output>10</output>

<gadget id="calculator">15 + 10 + 120</gadget>
<output>145</output>

<gadget id="calculator">1 + (2/3)</gadget>
<output>5/3 = around 1.666667</output>

<gadget id="calculator">145 / (5/3)</gadget>
<output>87</output>

<result>87</result>