These are the take off limiting codes. They indicate the two most limiting performance factors for the take off.
For example, usually:
1) 1st segment
2) 2nd segment
3) Runway length
4) Obstacle
5) Tyre speed
6) Brake energy
7) Max weight
8) Final take off
9) VMU
If the two codes are the same (as in your "3/3" example) it means that single factor is always more limiting than any other.
You should find all the relevant detail in the performance manual.