What are the rules of 1.22 2.27 4.05 5.10 6.12 7.18

What are the rules of 1.22 2.27 4.05 5.10 6.12 7.18

Is your question wrong? The last two are 6.13 7.18 or 6.12 7.17?
Each two groups, (1.22 2.27) (4.05 5.10) (6.13 7.18) difference was 1.05