The school originally planned to invest 240,000 yuan in the construction of the playground, but the actual investment was 180,000 yuan to achieve the goal. How much investment has actually been saved compared with the plan.
学校原计划投资24万元建筑操场，实际投资18万元就实现了目标．实际比计划节约了投资多少．
<gadget id="calculator">24 - 18</gadget>
<output>6</output>

<gadget id="calculator">6 / 24</gadget>
<output>1/4 = around 0.25</output>

<result>1/4 = around 0.25</result>