There were 11.58 tons of coal in the warehouse, and 15 tons were shipped in, and 5.85 tons were used. How many tons are left?
仓库里原有煤11.58吨，又运来15吨，用去5.85吨，还剩下多少吨？
<gadget id="calculator">15 - 5.85</gadget>
<output>9.15</output>

<gadget id="calculator">11.58 + 9.15</gadget>
<output>20.73</output>

<result>20.73</result>