Uncle Zhang went shopping in the supermarket, paid 100 yuan, and bought 3 bags of rice, each bag b yuan. How much should the salesperson get back?
张大伯到超市购物，付出100元，买了3袋大米，每袋b元．营业员应找回多少元．
<gadget id="calculator">100 - 3</gadget>
<output>97</output>

<result>97</result>