A pile of coal is 720 tons, originally planned to burn for 120 days. The actual coal burning is 4.5 tons per day, how many tons is actually saved per day compared with the plan?
一堆煤720吨，原计划可烧120天．实际每天烧煤4.5吨，实际每天比计划节约多少吨？
<gadget id="calculator">720 / 120</gadget>
<output>6</output>

<gadget id="calculator">6 - 4.5</gadget>
<output>1.5</output>

<result>1.5</result>