Can I install different size RAM modules?

Question

Iron

Hello,
I doubt whether it is possible to put memory modules of different sizes on my laptop? As I understand it, it is possible if the channels in the motherboard are different (correct if I'm wrong), but I would like to make sure. I did not see such information in the manual, so I turn to you.
Actually the Lenovo z50-70 model itself. Motherboard Lancer 5A5.
I don't know much about hardware, so I apologize if the question seems stupid.

Answer 1

Say, laptops are sold with 6 G of memory (2 + 4). And everything is OK.
If you buy memory - it's better with a check. They came to the seller with a laptop, tried it, it went - they bought it.