**Excel allows you to do all kinds of calculations** and respect mathematical rules (addition, subtraction, multiplication, division) and also how to perform operations that use several different operators without making any mistakes 😉

## The = sign

In Excel, all the calculations or formulas start with the = sign. **It's COMPULSORY !!!**

## Add values

To add values in Excel, you just have to write in any cell an operation like this one.

=10+5

In the cell, you see the result and in the formula bar, you see the formula 😉

Take care when you delete the contain of a cell, you could delete a formula and not a value.

## Subtract values

In the same way, to subtract values, you simply write a formula like this

=25-20

=20-25

## Multiplication and division

Here again, to make a multiplication or division, you just have to write the operation in a cell and you start with **the sign =**

=2*12 =>24

=50/10 =>5

### Order of operations

In math, all the operators don't have the same "power". That's what is called the order of operations.

Multiplication and division **have a stronger rank** than addition and subtraction.

### Wrong example of calculation

What is the result of this calculation **2+3*4**?

- Many will say the result is 20. If you start from the left, you have
**2+3**, so it's**5**. - And after, you have
**5**(the result of the 2 first values)**times 4**so result**20**

But this solution doesn't respect the order of operations

### Correct solution

In fact, **Excel starts with multiplication**.

- So first it's
**3*4=12** - Then, we do
**2+12=14**

And this is the result returns in the cell 😃

### Use parenthesis

If you want to **calculate the addition before the multiplication it's possible**. For that, you must write the addition in parenthesis

=(2+3)*4

This is because, in the order of operations, you have

- The parenthesis
- Multiplication and division
- Addition and subtraction

This point is very important to calculate VAT for instance.

## Facebook game

I'm sure you have seen this game in your Facebook timeline. But when you look at the answers in the comments, ... so many people don't respect the mathematical priority 😲😲😲

But if you follow the order of operations, it's easy to find the correct result.

The solution is the following

- Row 1: 3 beer bottle = 30.
- A bottle of beer it's 10 =30/3 (ok for every one? 😉)

- Row 2: 1 beer bottle + 2 hamburgers = 20
- We know that a beer bottle = 10
- So 2 hamburgers = 10 (20-10)
- 1 hamburger it's 5 =10/2

- Row 3: (here is the trick) 1 hamburger + 4 pintes = 13
- 1 hamburger = 5
- Here we have 2 group of 2 pintes. So there is 4 pintes
- So, 13-5 (the hamburger) = 8. And 8/4=2.
- The pinte = 2

- Row 4: 1 hamburger + 1 pinte * 1 beer bottle = ?
- So,
**you must respect the prior of the mathematical symbols** - 1 pinte * 1 beer bottle => 2*10 = 20
- 20 + hamburger => 20+5 = 25 😉

- So,