280/70-30 To change the order of operations to calculate subtraction first and then divide, how much should the formula be changed to?
280/70-30要改变运算顺序为先算减法再算除法，算式应改为多少．
<gadget id="calculator">70 - 30</gadget>
<output>40</output>

<gadget id="calculator">280 / 40</gadget>
<output>7</output>

<result>7</result>