As the Spring Festival is approaching, Hualian Supermarket purchased 540 small Chinese knots, which is 60 fewer than the four times the large Chinese knots it purchased. How many Chinese knots do supermarkets buy? (column equation solution)
春节快到了，华联超市购进小中国结540只，比购进的大中国结的4倍少60只．超市购进大中国结多少只？(列方程解答)
<gadget id="calculator">540 + 60</gadget>
<output>600</output>

<gadget id="calculator">600 / 4</gadget>
<output>150</output>

<result>150</result>