How to Multiply 4x4 Matrices Using a 3x3 Calculator?

[transgalactic]

i am given two matrices 4X4

which i need to multiply by one another

but in my calculator i can multiply matrices only 3X3

how can i use this maximum 3X3 matrices multiplication
in order to calculate the multiplication of two 4X4 matrices
??
(i know how to multiply matrices in theory but i want to shorten the process)

my calculator inputs matrices till m<=3 n<=3

i can't multiply 4X4 matrices one by one another
with the help of my calculator.

is there any mathematical methods of solving this without doing the formal way?

using smaller multiplications which could be done in my calculator

 

[fresh_42]

This is more work than doing it by hand. I suggest the calculator in here:
https://www.physicsforums.com/threa...th-and-other-curiosities.970262/#post-6164027