There can be two math lessons on one day, but they need to be placed consecutivelly

If you have 6 math lessons per 5 day week, then two will be on one day. In this case you can tell the software to place these consecutivelly:

Add a new cardrelationships and select entries marked by red color:

The green color is optional, if for example you have 6 math lessons, the software will by default spread them on 5 days(one day will have two lessons).

But you can tell the software to place 6 lessons on 4 days. Or as shown on the picture you can let the software to decide if 6 maths will be on 4 days or 5 days.

See also:
There can be two maths on one day, but not consecutivelly

Chceli by sme mať hodiny za týždeň rozdelené 1+1+1+2 ALEBO 1+2+2.