__maths__>__Properties of Vector Arithmetics__>__Properties of Vector Multiplication by Scalar__### Order of Scalar Multiplication

In this page, you will learn about order of multiplication : multiplication of a vector by a scalar and multiplication of a scalar by a vector.

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What is the difference between

• Multiplication of a scalar by a vector

• Multiplication of a vector by a scalar ?

- both are identical
- both are identical
- multiplication of a scalar by a vector is not defined

The answer is 'both are identical'. The multiplication of a scalar by a vector is not observed in practical applications. But with mathematical abstraction, it is defined.

• Multiplication of a vector by a scalar is equivalently multiplication of a scalar by a vector. *(Note: This is not called "commutative property".)*

**Order in Multiplication by scalar: **Given a scalar `lambda` and vector `vec p`

`lambda vec p = vec p lambda`

*Solved Exercise Problem: *

Given `vec p= 2.1i+1.5j-3k` what is the value of `vec p 2`?

- `2.1i+1.5j-3k2`
- `2.1i+1.5j-6k`
- `4.2i+3j-6k`
- `4.2i+3j-6k`

The answer is '`4.2i+3j-6k`'.

*slide-show version coming soon*