IRuby.display(Complex(1,2))

$1+2\imath$

require 'matrix'
IRuby.display(Matrix[[1,2],[3,4]])
IRuby.display(Matrix[[1,2],[3,4]],format:'latex')
IRuby.display(Matrix[[1,2],[3,4]],'text/plain')
IRuby.display(Matrix[[1,2],[3,4]],mime:'text/plain')
IRuby.display(Matrix[[1,2],[3,4]],'html')

$$\left(\begin{array}{cc} 1&2\\ 3&4\\ \end{array}\right)$$

$$\left(\begin{array}{cc} 1&2\\ 3&4\\ \end{array}\right)$$

Matrix[[1, 2], [3, 4]]

Matrix[[1, 2], [3, 4]]

1	2
3	4