The Handy Math Answer Book

A 3 by 2 (3 2) matrix:

A 2 by 3 (2 3) matrix:

A 4 by 4 (4 4) matrix (when the row and column dimensions are the same, it is

called a “square matrix”):

How do you add matrices?

It is pretty easy to add matrices. For example, for (1 2) ( 1 2), you add the matri-

ces (or in this case, row numbers) simply by adding the corresponding terms in each

matrix. Thus, the matrix of (1 2) ( 1 2) (1 12 2) (0 0).

1

5

9

4

2

6

1

5

3

7

2

6

4

8

3

7

R

T

S

S

S

S

S

V

X

W

W

W

W

W

1

4

2

5

3

6

= G

1

3

5

2

4

6

R

T

S

S

SS

V

X

W

W

WW

158

Did the Mayans know about matrices?

S

ome scientists believe that the Mayan culture had a good working idea about

matrices long before they became a part of mathematics. It is thought that

the Mayans discovered how to place a set of “numbers” in columns and rows,

then performed diverse operations on them, such as a method of adding and

subtracting along diagonals to solve “equations” with unknown quantities. They

may have even used the matrices for multiplication, division, and calculations of

square and cubic roots on a matrix array by using a series of dots in a matrix to

perform the operations. And there is evidence of these mathematical squares on

their monuments, paintings, and on garments, including those of the Mayan

priests and on crests of higher officials. But not everyone agrees with this

notion; some scientists believe that the Mayan grids are merely mimicking

objects in nature, such as the back of a turtle’s shell.