Xiaohua and Xiaoying went to the store at the same time and bought a 20cm pencil each. After two weeks of use, Xiaohua’s pencil had 8.4cm left, and Xiaoying’s pencil had 10.8cm left. Whoever used it more should use more How many centimeters have you gone?
小华和小英同时到商店各买了一支20厘米的铅笔，用了两个星期后，小华的铅笔还剩8.4厘米，小英的铅笔还剩10.8厘米，谁用去的多，多用去了多少厘米？
<gadget id="calculator">20 - 8.4</gadget>
<output>11.6</output>

<gadget id="calculator">20 - 10.8</gadget>
<output>9.2</output>

<gadget id="calculator">11.6 - 9.2</gadget>
<output>2.4</output>

<result>2.4</result>