Matrix Multiplication Definitions

M N =P if and only if the number of columns of matrix M is the same as the number of rows of matrix N and

p_ij = m_i1n_1j + m_i2n_2j+ m_i3n_3j + ... + m_ikn_kj.

The matrix P has the same number of rows as M and the same number of columns as N.

If a multiplication cannot be performed because of the order of given matrices, the matrices are said to be not conformable.

A is the first matrix or set of data.

a₁₁=row 1 and column 1
a₁₂=row 1 and column 2
a₂₁=row 2 and column 1
a₂₂=row 2 and column 2

B is the second matrix or set of data.

b₁₁=row 1 and column 1
b₁₂=row 1 and column 2
b₂₁=row 2 and column 1
b₂₂=row 2 and column 2

A * B is the mutiplication of matrix A times matrix B.