Matrix subtraction not working as it should

Questions
1

All I want to do is subtract Ab and Bb and then have the result as one matrix.
Please help
I don’t get why it shows both matrices on either side of a minus sign. Any ideas?

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2

Try removing the postfix MatrixForm wrapper.

3

Already tried that. Does not work

4

This is what Daniel told you to do:
https://www.wolframcloud.com/obj/outreach/Published/AliMatSub.nb

5

You probably didn’t try it everywhere then. To be clear, when you did this,

R1R2 = R1 . R2 // MatrixForm

You assigned to R1R1 an expression with head MatrixForm. Try evaluating this:

FullForm[R1R2]

There is no built in arithmetic defined for MatrixForm. MatrixForm is just a wrapper for display purposes. The convention I use when I want to see a nice representation of a thing is to separate the definition from the display:

R1R2 = R1 . R2; R1R2 // MatrixForm

If you do this throughout your notebook, you’ll get what you’re looking for.

6

Thanks a lot. I apologize for the misunderstanding on my end