What is the difference between these model numbers?

Solution
What I do is go to ASUS's website and print out the detailed specs of each motherboard variant and compare. I find it much easier to just have pages spread out on a table and check off what each have in common, then look at what they do not have in common with each other. Here's the specs of the M-K variant of an example of what to print out:

https://www.asus.com/us/Motherboards/H110M-K/specifications/

Much of these categories you can just cross out since obviously they are all going to be the same like CPU, Chipset, Memory, and Graphic. What you'll need to pay attention to are these categories for what has something that the other does not and vice versa:

Expansion Slots (PCIe)
Storage (SATA connectors)
LAN Controller
Audio
Back...
What I do is go to ASUS's website and print out the detailed specs of each motherboard variant and compare. I find it much easier to just have pages spread out on a table and check off what each have in common, then look at what they do not have in common with each other. Here's the specs of the M-K variant of an example of what to print out:

https://www.asus.com/us/Motherboards/H110M-K/specifications/

Much of these categories you can just cross out since obviously they are all going to be the same like CPU, Chipset, Memory, and Graphic. What you'll need to pay attention to are these categories for what has something that the other does not and vice versa:

Expansion Slots (PCIe)
Storage (SATA connectors)
LAN Controller
Audio
Back I/O Ports
Internal I/O ports

^^ That is where the majority of your differences are going to be between models. Figure out what is more important to you like more USB ports on the back (I/O Ports) and whatnot. And then make your choice.

Now it gets more complicated the higher up in the chipset you go because some ASUS motherboards have higher quality capacitors and more phases than others, but I don't see that issue with H-series boards from ASUS. I'm talking Z-level and above, and that's where you really need to read detailed reviews of said boards on tech sites like this.

 
Solution