A T-shirt is now priced at 120 yuan, which is 20% lower than the original price. How much is the original price?
一件T恤衫现在售价120元，比原价降低了20%，原价是多少元？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">120 / (4/5)</gadget>
<output>150</output>

<result>150</result>