Excel allows you to do all kinds of calculations and respect mathematical rules.
We will see how to perform simple calculations (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 !!!
To add values in Excel, you just have to write in any cell an operation like this one.
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.
In the same way, to subtract values, you simply write a formula like this
But if you write switch the 2 values, the result is not the same
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 =
Let the fun begins
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
In fact, we must start by the multiplication.
- So first it's 3*4=12
- Then, we do 2+12=14
And it's the result returns in the cell 😃
I'm sure you have seen this game in your Facebook timeline and when you look in the answers in comment, are ... WOW 😲😲😲
But if you follow the order of operations, it's easy to find the correct result.
- 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 😉
Let's return to our first example 2+3*4
If you want to calculate the addition before the multiplication it's possible. For that, you must write the addition in parenthesis
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.
Calculation with reference
Ok, use Excel with values in the calculation it's easy. But the best, is to re-use the contain of other cells in the formula.
The same rule of order of operations works with values and references
Percentage increase between 2 values
You can use exactly the same maths operators to calculate the percentage increase between 2 values.
This calculation is one of the most useful in Excel 😉. Have a look at this page for the explanation