# Evaluate an expression/formula

We can find the value of an expression when given the values of , , etc.

Before we start, we will need to remind ourselves of : the order in which we carry out calculations.

Question

Find the value of when and .

To find the value of an expression, we need to substitute the given values for and into .

Remember, BODMAS tells us to multiply before we add.

Question

Evaluate when , and .

Question

An approximate formula which converts celsius temperatures to farenheit is .

Calculate when is 15.

Therefore 15°C is approximately equal to 60°F.