Substitute Numerical Values into Expressions

In this activity, we'll be learning how to substitute given values into expressions.

We use algebra when we don't know the exact numbers in a calculation, and to do this we use letters to stand for numbers that we are trying to find.

If we then get a value for that letter, we can swap them or substitute the value in!

What do we mean by this?

Well, if a bottle of cola is £2, we know if we want more than one bottle we have to multiply the number by £2

We can write 2x for the unknown quantity of bottles of cola.

If someone asks for 3 bottles, we can substitute the x for 3:  3 lots of £2 = £6

Likewise, if someone asks for 5 bottles, we can substitute the x for 5:  5 lots of £2 = £10

Does that make it clearer?

Let's have a go at some questions - you have got this!