凡其为此物也,无不加用而为者,是故用财不费,民德不劳,其兴利多矣。
凡是圣人制造的这些东西,无一不是有益于实用才去做的,所以使用财物不浪费,民众能够不劳苦,他兴起的利益太多了。
Don’t wait until they tell you you are ready. The world might say you are not allowed to yet. I waited a long time in the world before I gave myself permission to fail. Please, Don’t even bother asking, don't bothering telling the world you are ready. Show it. Do it.
小于给定数的素数个数是该数的一个函数。