• Operators are used in programming to assign new values, compare values, test values, update values, perform arithmetic on values, etc.
• operators are used to manipulate variables in a number of ways.
• So far, we’ve only really dealt with the default assignment operator, =, like when we say:

var usingAssignmentOperator = "<-- Thats the common assignment operator";

• In total, there are seven categories of operators in JavaScript.
• These include operators for
  • arithmetic operations,
  • assignments,
  • string operations,
  • comparisons,
  • logical operations,
  • conditional operations, and other types of operators that are worth mentioning.
    

Arithmetic Operators

• JavaScript’s arithmetic operators are used to perform arithmetic in your code.
• Arithmetic operators each have a symbol known as the operator that is used to perform the operation.
• Addition : adding two values or variables together
  • Operator: +
    

  let sum = 5 + 7000;
  let x, y;
  x = 20;
  y = 30;
  let z = x + y + 400; 

• Q : What is the value of variable z?

• Subtracting : subtracting one value or variable from another
  • Operator: -
    

  let minus = 300 - 87;
  let a, b;
  a = 83;
  b = 65;
  let c =  a - b; 

• Q : What is the value of variable c?

• Multiplication : multiplying multiple values or variables together
  • Operator: *

  let product = 75 * 39;
  let j, k;
  j = 14;
  k = 92;
  let l = j * k * .5; 

• Q : What is the value of variable l?

• Division : dividing one or more values or variables by another
  • Operator: /

let quotient = 5016 / 6;
let q, w;
q = 46;
w = 138;
let p = (w / q) / 3; 

• When there are multiple operations on a single line, the answer is calculated in the order of PEMDAS
• Q : What is the value of variable p?

• Modulus : retrieving the remainder of one or more values or variables being divided by another
  • Operator: %

let modulus = 33%15; 
// the value of modulus would be 3, 
// because 32 goes into 15 twice, with left over.
let h = 46;
let i = 13;
let g = h % i;  

• Q : What is the value of variable g?

• Increment : increasing the value of a variable by 1 (adding 1)
  • Operator: ++

let someValue = 10;
someValue++;
let newValue = someValue++;

• Q : What is the value of the variable named newValue?

• Decrement : decreasing the value of a variable by 1 (subtracting 1)
  • Operator: –

// Examples:
let someOtherValue = 90;
someOtherValue--;
let anotherNewValue = someOtherValue--;

• Q : What is the value of the variable named anotherNewValue?

• The operators can be used on fixed values, such as:
  

let adding = 5 + 5;
let subtracting = 10 - 5;
let dividing = 40 / 5;
let multiplying = 80 * 3;
let modulus = 20 % 8;

• Arithmetic operators can also be used on variables:
  

let number = 50;
let newAdding =  adding + number;
let newSubtracting = subtracting - number;
let newDividing = number / dividing;
let newMultiplying = multiplying * number;
let newModulus = number % modulus;

• The operators can even be used with a mix of fixed values and variables:

newAdding =  adding + 30;
newSubtracting = subtracting - 23;
newDividing = 5 / dividing;
newMultiplying = multiplying * 7;
newModulus = 24 % modulus;

Exercise

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