how to get the missing numbers in a given item

Question

supply the missing numbers 9.12 18.13 16.15 13.18 9.22

Answer 1

Do you mean: 19.12, 18.13, 16.15, 13.18. 9.22?

The whole number parts are 19, 18, 16, 13, 9 with differences: 1, 2, 3, 4. So the next whole number part would be 9-5=4 so we have: 19, 18, 16, 13, 9, 4.

The fractions parts are 12, 13, 15, 18, 22 with differences 1, 2, 3, 4. The next fraction part would be 22+5=27. 

The next number in the sequence would be 4.27.