摘要：
Given any integer 0 ≤ n ≤ 10000 not divisibleby 2 or 5, some multiple of n is a number whichin decimal notation is a sequence of 1’s. Howmany digits a... 阅读全文
摘要：
Mathematicians love all sorts of odd properties of numbers. For instance, they consider 945 to be an interesting number, since it is the first odd num... 阅读全文
摘要：
The season of flying kites is well ahead. So what? Let us make an inventory for kites. We are givena square shaped sheet of paper. But many parts of th... 阅读全文