The quality of the rice in the two bags of A and B is equal. If 5 kilograms are taken out from bag A and 7 kilograms are added to bag B, then the rice in bag B is 4 times that of bag A. How many kilograms of rice does bag A have?
甲乙两个袋子的大米质量相等．如果从甲袋子取出5千克，乙袋子加入7千克，这时乙袋的大米是甲袋的4倍，甲袋原有多少千克大米？
<gadget id="calculator">5 + 7</gadget>
<output>12</output>

<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<result>9</result>