# How To Multiply Matrices - Quick & Easy! | Summary and Q&A

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October 5, 2018
by
The Organic Chemistry Tutor
How To Multiply Matrices - Quick & Easy!

## TL;DR

Learn how to multiply matrices together by understanding their sizes and the order of multiplication.

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### Q: How do you determine whether two matrices can be multiplied together?

Two matrices can be multiplied if the number of columns in the first matrix is equal to the number of rows in the second matrix.

### Q: What is the size of the resultant matrix when multiplying two matrices?

The resultant matrix will have a number of rows equal to the number of rows in the first matrix and a number of columns equal to the number of columns in the second matrix.

### Q: Is the order of multiplication important in matrix multiplication?

Yes, the order of multiplication is important. Not all combinations of matrices can be multiplied. The number of columns in the first matrix must equal the number of rows in the second matrix.

### Q: Can matrix B be multiplied by matrix A?

No, matrix B cannot be multiplied by matrix A because the number of columns in matrix B is not equal to the number of rows in matrix A.

## Summary & Key Takeaways

• Matrix multiplication requires the number of columns in the first matrix to equal the number of rows in the second matrix.

• The resultant matrix will have a number of rows equal to the number of rows in the first matrix and a number of columns equal to the number of columns in the second matrix.

• The order of multiplication is important, as not all combinations of matrices can be multiplied.