杰出的科学家牛顿，曾提出过一个耐人寻味的“牛吃草”数学问题：“一堆草可供１０头牛吃３天，能供６头牛吃几天？”这道题当然很简单，同学们一看就可算出来。但是，如果将“一堆草”换成“一片正在生长的草地”，问题就不那么简单了。因为草的数量在不断变化，像这类总的数? An outstanding scientist Newton once proposed an intriguing math problem: “A pile of grass can feed 10 cows for 3 days and can feed 6 cows for a few days?” This question is of course very simple. Students They can figure it out. However, if you change “bunch of grass” to “a piece of growing grass,” the problem is not that simple. Because the number of grass is constantly changing, like the total number of such?