Texas Instruments TI-84 - Manual (Page 236)

Chapter 10: Matrices 233
abs( abs( abs( abs(
abs( (absolute value, MATH NUM menu) returns a matrix containing the absolute value of
each element of matrix .
abs(matrix)
round( round( round( round(
round( ( MATH NUM menu) returns a matrix. It rounds every element in matrix to # decimals
(  9). If
#decimals is omitted, the elements are rounded to 10 digits.
round(matrix [, #decimals ] )
Inverse Inverse Inverse Inverse
Use the
L1
function (
œ) to invert a matrix (
^ L 1 is not valid). matrix must be square. The
determinant cannot equal zero.