Zhang Ming has 120 yuan, 80% of which is used to buy books, and 15% of the money to buy stationery. How much does it cost to buy stationery?
张明有120元钱，买书用去80%，买文具的钱是买书的15%．买文具用去多少元？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">15 / 100</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">120 * (4/5) * (3/20)</gadget>
<output>72/5 = around 14.4</output>

<result>72/5 = around 14.4</result>