摘要：
对于互质的两个数p，q，px+py 不能表示的最大数为pq-p-q. 证明： 先证:pq-p-q不能被px+py表示. 假设pq-p-q可以被px+py表示 那么 px+py=pq-p-q p(x+1)+q(y+1)=pq -> q|x+1 p|y+1 很明显x+1>=q p(x+1)>=pq 矛盾 阅读全文
摘要：
On the way home, Karen decided to stop by the supermarket to buy some groceries. She needs to buy a lot of goods, but since she is a student her budge 阅读全文