Basic Math Operators
Although Google Sheets has several functions, all start by using the basic math operators to understand the power of this spreadsheet. This post only covers the basic math operators for your understanding, I will post more on more advance features of Sheets.
Before any operator or function
Both Google Sheets and Microsoft Excel use the equal sign before an expression (=). You must include the = sign to tell the spreadsheets to calculate some expression.
Adding Numbers
The basic operator for adding numbers is + (the plus sign) ; you can add two or more numbers. You can add numbers in one cell or several numbers in several cells. Horizontally, vertically or even in different places.

Examples: (A) No result because no equal sign = in front of the equation. (B) Same equation, but = sign included, the result- 10. (C) Vertical Example – Numbers and formula in different cells, the result- 16. (D) Same as C, but using the cell references, the result- 16. (E) Horizontal Example – Adding to the side, the result- 19.
Substracting Numbers
The basic operator for substractiong numbers is – (the minus sign) ; you can substract two or more numbers. You can substract numbers in one cell or several numbers in several cells. Horizontally, vertically or even in different places.

Examples: (A) No result because no equal sign = in front of the equation. (B) Same equation, but = sign included, the result- 3. (C) Vertical Example – Numbers and formula in different cells, the result- 14. (D) Same as C, but using the cell references, the result- 14. (E) Horizontal Example – Adding to the side, the result- 1.
Important Note: Google Sheets manage different types of numbers such as integers, real, decimals, and percentages. You can format these numbers to your needs. Remember that numbers can either be positive or negative, depending on the calculation.
Multiplication and Division
As stated before, Google Sheets capabilities allow you to use several operators and functions to do faster and automate your work. Two basic operators that you will find very useful are multiplication * (asterisk sign) and / (slash sign).

In both cases, the multiplication and division show that you can obtain values by multiplying or dividing with different numbers format or cell addresses.
Parenthesis ( )
Although, the parenthesis is not an operator. It is very useful to understand its use. If you want to deepen your knowledge into formulas and functions, and create your own solutions, then parenthesis is one of the keys to your success. The idea behind parenthesis, it shows presedence between calculations. Thus, if you have the following:
= (4 * 5) + 7 – 4 = 23; this is not equal to 4 * (5 + 7) – 4 = 44 Why?
The parenthesis tells Google Sheets that the expression inside must be solved first then the outside. Division, multiplication, addition and substract in that order.
Conclusion:
Using the math operators and parenthesis, will improve and automate several taks in Google Sheets. Most of the topics covered, also applies to Microsoft Excel, thus you will benefit from it. My advise to you, explore and test based on your necessities so you can obtain your best results.