A bottle of oil weighs 500 grams. After eating 10% of the oil, how much does the bottle of oil weigh now?
一瓶油重500克，吃掉10%后，这瓶油现在重多少克．
<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">1 - (1/10)</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">500 * (9/10)</gadget>
<output>450</output>

<result>450</result>