Then, A+B = ⎟⎟
⎠
⎞
⎜⎜⎝
⎛
+ − +
− +
3 5 4 6
1 3 2 4
= ⎟⎟
⎠
⎞
⎜⎜⎝
⎛−
8 2
2 6
Note that A + B = B + A. That is, matrix addition is commutative. If we are adding
three matrices together then we can observe that matrix addition is associative also.
The idea could be taught to the child through the magnetic board supported by
necessary reading material in Braille.
- Subtraction of Matrices
Subtraction of two matrices is possible only if the matrices are of the same order.
Eg. : If A = ⎟⎟⎠
⎞
⎜⎜⎝
=⎛
⎟⎟⎠
⎞
⎜⎜⎝
⎛
− 2 5
1 3
andB
4 6
3 5
Then, A – B = ⎟⎟
⎠
⎞
⎜⎜⎝
⎛
− − −
− −
4 2 6 5
3 1 5 3
= ⎟⎟
⎠
⎞
⎜⎜⎝
⎛
2 − 11
2 2
Note that A – B ≠ B – A. Hence commutative property does not hold good with
respect to matrix subtraction.
- Multiplication of Matrices
Two matrices A and B can be multiplied together, if the number of columns of the first
matrix A is equal to the number of rows of the second matrix B.
