Xiaohong and Xiaohua go to the bookstore together. They want to buy a comic book. Xiaohong's money is worse than 2 yuan's, and Xiaohua's money is worse than 1 yuan's 6 cents. The money of the two is combined. You need 3 yuan 60 cents. You can explain this to your children: Because the two children can buy this book together, it proves that Xiaohong's 2 yuan money is Xiaohua's money, and Xiaohua can buy it by giving him his 2 yuan money. Similarly, Xiaohua has a price difference of 1 yuan 60 cents, so it is enough to give Xiaohong's money, which means that his price difference of 1 yuan 60 cents is Xiaohong's money, so Xiaohong has 6544.