The chair is 40 yuan cheaper than the desk, and the unit price of the chair is 50% of the desk. Looking for the unit price of this set of tables and chairs?
椅子比桌子便宜40元，椅子的单价是课桌的50%．求这套桌椅的单价？
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 - (1/2)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">40 / (1/2)</gadget>
<output>80</output>

<gadget id="calculator">80 - 40</gadget>
<output>40</output>

<gadget id="calculator">40 + 80</gadget>
<output>120</output>

<result>120</result>