Mr. Zhang bought 5 volleyballs, each volleyball a yuan, and paid 150 yuan to the salesperson, how much should he get back.
张老师买了5个排球，每一个排球a元，付150元给营业员，应找回多少元．
<gadget id="calculator">150 - 5</gadget>
<output>145</output>

<result>145</result>