1: The money for each exercise book is 5.1-2× [5.1-(8.4-5.1)] =1.5 yuan. Money per pencil (5.1-(8.4-5. 1))-1.5 = 0.3 yuan (resolution: 8.4-5.1means money for 2 exercise books and 2 pencils, 5./kloc-0.

2: 1 thermos bottle costs 58÷4= 14.5 yuan; A tea set 14.5×2=29 yuan (analysis: from "the price of three tea sets is equivalent to the price of six thermos bottles", we can know that "1 tea set is equivalent to the price of two thermos bottles", so it is 58÷4= 14.5).

3: per kilogram of rice: (16.72-10× 0.32) ÷16 = 0.845; 0.845+0.32= 1. 165 yuan per kilogram of flour. (Analysis: From the two ways of purchasing, we know that flour is 0.32 yuan more expensive than rice per catty, so 10× 0.32 yuan is more expensive than 10×0.32 Jin, so 16.72- 10×0.32 means/kloc-.