There are five bags of rice in the warehouse. If 20 kilograms are taken out of each bag, the mass of the remaining five bags of rice is exactly the mass of the original four bags of rice. What is the original mass of each bag of rice in kilograms?
仓库里有五袋大米，如果从每个袋子里都取出20千克，那么剩下的这5袋大米的质量正好是原来4袋大米的质量，原来每袋大米的质量是多少千克？
<gadget id="calculator">5 - 4</gadget>
<output>1</output>

<gadget id="calculator">5 / 1</gadget>
<output>5</output>

<gadget id="calculator">20 * 5</gadget>
<output>100</output>

<result>100</result>