Before starting with numbers let’s look at some common arithmetic operators which we can use with numbers.
Addition (+), Subtraction (-), Multiplication (*), Division (/), and Modular (%) these are most common arithmetic operators we use to perform mathematical operations on numbers.
Let’s use these operators with numbers.
let result; let a = 20; let b = 30; result = a + b; console.log(result);
We have created 3 variables. One to store results and others (a & b) are holding values. By using (+) sign we are adding those variable’s values and storing into result variable.
In the console log, you should see result is 50.
let result; let a = 30; let b = 10; result = a - b; console.log(result);
For Subtraction, we have used minus (–) sign. In the console log you will get an answer 20.
Normally for multiplication we use X sign. But in programming languages we use asterisk * for multiplication. Let’s see example.
let result; let a = 3; let b = 5; result = a * b; console.log(result);
For multiplication, we have used * sign. You will get an answer 15 in console log.
let result; let a = 10; let b = 5; result = a / b; console.log(result);
For division, we have used / sign. You will get an answer 2 in the console log.
For modulo we use percentage (%) sign. It basically returns remainder after division. Let’s see the example.
let result; let a = 7; let b = 3; result = a % b; console.log(result);
We have used % sign between a and b variables. You will get an answer 1 in the console log.
Increment (++) & Decrement (- -) Operators
When we use ++ operator as postfix (means after the number or numeric variable) it returns value first and then increment and then returns incremented value.
When we use ++ operator as prefix (means before the number or numeric variable) it increments first and returns value.
If explanation seems confusing 😕 let’s see the example.
Increment (++) Example
let a = 22; console.log('a1 =' , a++); console.log('a2 =' , a); let b = 22; console.log('b1 =' , ++b); console.log('b2 =' , b);
We have declared two variables (a & b) with same value.
For a variable, we are logging a++ (postfix) value & on the next line we are logging a value. Results are:
a1 = 22 & a2 = 23
You can see that even if we have used ++ after variable it doesn’t increment value at a1 but at a2 it has increment value. So, now read the above statement for postfix you will get more clarity now.
For b variable, we are logging ++b (prefix) value & on the next line we are logging b value. Results are:
b1 = 23 & b2 = 23
Here for prefix, value gets incremented first. Thus, value for both b1 and b2 logs are same. Read the above statement for prefix you will get more clarity now.
Decrement (- -) Example
Decrement is almost same as increment. It is just that in decrement value gets subtracted instead of addition. Let’s see the example.
let a = 22; console.log('a1 =' , a--); console.log('a2 =' , a); let b = 22; console.log('b1 =' , --b); console.log('b2 =' , b);
You can see that we have used – – sign with variables a and b.
Results for variable a:
a1 = 22 & a2 = 21
Results for variable b:
b1 = 21 & b2 = 21
You can also define negative numbers same way as postive numbers. For exmaple.
let amount = -50; console.log(amount);
You will get -50 in console.
If you want to add or minus negative number then make habit using brackets. For example:
let result = 22 + (-7); console.log(result);
Answer of above is 15. You can see in console. By using brackets you make sure that your mathematical operation will as expected.