Video: https://youtu.be/5pRWaIOAxyk
Code from this video: https://jsfiddle.net/s28jmn4q/6/
Operators summary
In programming world, operators are reserved symbols that you can use to perform mathematical or logical operations. You can use them for arithmetic or for checking if a variable is equal to a value or to another variable and much more of course.
The following are the common types of operators that you will usually be working with:
Arithmetic
We can use arithmetic operators to perform operations such as addition, subtraction, multiplication and division.
Symbol  Operation  Usage  Details 

+  addition  x + y  add y to x 
  subtraction  x  y  subtract y from x 
*  multiplication  x * y  multiply x with y 
/  division  x / y  divide x by y 
// Addition
let a = 5 + 5
console.log(a) // 10
// Subtraction
let s = 10  5
console.log(s) // 5
// Multiplication
let m = 5 * 2
console.log(m) // 10
// Division
let d = 4 / 2
console.log(d) // 2
Assignment
You already saw one example of this in the previous section where we went over variables  that is assigning a value to a variable. We have a few more assignment operators than just the =
one.
Symbol  Operation  Usage  Same as  Details 

=  assignment  x = y  assignes whatever value is in y to x 

+=  add and assignment  x += y  x = x + y  assignes to x the result of adding y to x 
=  minus and assignment  x = y  x = x  y  assignes to x the result of minusing y from x 
*=  multiply and assignment  x *= y  x = x * y  assignes to x the result of multiplying x with y 
/=  divide and assignment  x /= y  x = x / y  assignes to x the result of dividing x by y 
// Assignment
let name = "John Doe"
console.log(name) // John Doe
// Add and assignment
let x = 5
x += 5 // x = 5 + 5
console.log(x) // 10
// Minus and assignment
let x = 5
x = 3 // x = 5  3
console.log(x) // 2
// Multiply and assignment
let x = 5
x *= 2 // x = 5 * 2
console.log(x) // 10
// Divide and assignment
let x = 4
x /= 2 // x = 4 / 2
console.log(x) // 2
Comparison
We use comparision operators to do comparisons. They result to either a true or false value (Boolean) based on whatever comparision is being made. For example, we can use comparision operators to check if two variables are equal or unequal.
Symbol  Operation  Usage  Details 

==  equal  x == y  checks if x equals y  If equals the comparision results to true 
!=  not equal  x != y  checks if x does not equal y  If not equals the comparision results to true 
>  greater than  x > y  checks if x is greater than y  If greater the comparision results to true 
<  less than  x < y  checks if x is less than y  If lesser the comparision results to true 
>=  greater than or equal  x >= y  checks if x is greater than or equal to y  If is greater than or equal the comparision results to true 
<=  less than or equal  x <= y  checks if x is less than or equal to y  If is less than or equal the comparision results to true 
// Equal
console.log(5 == 5) // true
console.log(5 == 4) // false
// Not equal
console.log(5 != 6) // true
console.log(5 != 5) // false
// Greater than
console.log(5 > 4) // true
console.log(5 > 6) // false
// Less than
console.log(5 < 6) // true
console.log(5 < 4) // false
// Greater than or equal
console.log(5 >= 5) // true
console.log(5 >= 4) // true
console.log(5 >= 6) // false
// Less than or equal
console.log(5 <= 5) // true
console.log(5 <= 6) // true
console.log(5 <= 2) // false