Try to start by reading the manual it came with. If it didn't come with a manual, then your teacher in school will teach you how to use it for specific commands. Otherwise it's just like using a regular calculator but with the ability to do more things, what do you need to know on it?
Note how we can distribute the 10 back in to check our work 10(2k+5) = 10(2k)+10(5) = 20k+50 so that confirms we have the right answer
Another thing to notice is that 10 is the largest factor that we can pull out of 20k and 50. The value 10 is the GCF (greatest common factor) of 20 and 50.
