An old woman took out 1,000 yuan to buy commemorative stamps at the post office. She asked to buy some 50 yuan stamps. Buy 20 yuan stamps five times more than this, and buy the rest 80 yuan stamps, just to use up the money, how many stamps of each denomination should be given to her.
一位老妇在邮局拿出1000元购买纪念邮票．她要求买若干枚50元的邮票．再买5倍于此的20元邮票，余下的买80元邮票，刚好把钱用尽，应该给她每种面值的邮票共多少枚．
<gadget id="calculator">5 * 4</gadget>
<output>20</output>

<gadget id="calculator">4 + 20 + 5</gadget>
<output>29</output>

<result>29</result>