For example:

7 x1= 7 27

X2=14 24

X3=21 21

X4=28 18

X5=35 15

X6=42 12

X7=49 9

X8=56 6

X9=63 3

Where the second digit seems to be or part of a multiple of 3 in reverse order (or from 9 back to 1).

If I do this with multiplying 3, the second digits are multiples of 7 in reverse order. I did this with all numbers from 1-9 and they all had this type of partnership with another number.

1 and 9

2 and 8

3 and 7

4 and 6

5 with itself

Again, does this have a name/significance or is it just a coincidence and irrelevant?

TIA