I need subject Math to be on the same position in classes 5.A and 5.B

Please go to menu - Specification/Card relationships/Add.
Use card relationship: "The selected subjects have to be at the same time in all selected classes."
See picture:

Notes:

1) For 5C+5D, you will need to specify another card relationship.

2) If you want this constraint also for English lessons, you will also need to create another card relationship. That is, you will have one card relationship for Math and one for English. (If you select two subjects in single cardrelationsip, it has different meaning, see 3)

3) It is also possible to say that two (or more) subjects must be on the same positions in 5.A and 5.B:

See also:
Groups have to start at the same time