Explanation

A scalar is a single number.

Scalar multiplication means multiplying every entry in a matrix by that number.

Example:
3 ×
[ 1 2 ]
[ 4 5 ]

=
[ 3 6 ]
[12 15 ]

Rules:

• Multiply each entry

• Dimensions stay the same

Quiz

1. What is a scalar?

2. Multiply 2 by [1 −3].

3. Does scalar multiplication change dimensions?

4. What happens if the scalar is 0?

5. Is scalar multiplication reversible?

Answer Key

1. A single number

2. [2 −6]

3. No

4. All entries become 0

5. Yes (if scalar ≠ 0)