How can I make 80 percent of the matrix values equal to zeros, randomly?

I have a matrix A (30 by 20). I want to generate three random matrices, each containing 20 percent of the orgional matrix. In other words, I want to replace 80 percent values of A matrix to zeros but randomly. Thank you

Answer 1

[KSSV]

A = rand(30,20);   % Matrix for demo 
B = A ; 
idx = randperm(numel(A),round(numel(A)*80/100)) ; % get 80% of indices randomly 
B(idx) = 0 ;  % replace with zero 

[Khan]

Thank you so much and How can I save it as a new matrix?

[KSSV]

Edited the answer.