index.html

<!-- in this lesson: -->
<!-- ------------------- -->
<!--

    Lesson 2 :  Numbers & Math

    1.  Numbers & Math.
    2.  Order of Operations & Brackets.
    3.  Calculations using Floats can be inaccurate.
    4.  Math.round()

-->

<script>
	//🟨 Console :-

	10 + 2

	10 - 2

	10 * 2

	10 / 2

	2 + 2 + 3

	2.5 + 2.5

	10.9 * 2 + 20.95

	42.75 + 4.99

	10.9 * 2 + 20.95 + 4.99

	//🟨 Order of Operations (+ - / *  are Operators) :-

	//🟦 1.  (...)
	//🟦 2.  * /
	//🟦 3.  + -

	1 + 1 * 3 // Multiplication (*) & Division (/)  --Done 1st--.   1 + 3 = 4 :-

	//  🟨We can use (...)
	//  🟨to control which part gets --Done 1st--
	;(1 + 1) * 3 // =>  (2) * 3 = 6

	//  🟨Syntax Rules of Brackets  !! SYNTAX ERROR :-
	//  ( 1 + 1 * ( 3       // This will not work

	20.98 + 7.99 * 2

	//  36.93 * 10%  ❗❌
	//  1% = 1 / 100    per / cent
	//  10% = 10 / 100 = 0.1

	36.93 * 0.1 // = 3.693

	20.95 + 7.99 * 2 * 0.1 //    = 22.548
	;(20.95 + 7.99 * 2) * 0.1 //    = 3.693

	//                                      🟨  Calculations with Floats are sometimes inaccurate When working with money
	20.95 + 7.99 //   28.939999999998       ⛔  INSTEAD OF DOING THIS FOR '$' DOLLARS
	2095 + 799 //  2894                     ✅  1st DO THE CALCULATIONS IN CENTS
	;(2095 + 799) / 100 //  28.94           ✅  CONVERT BACK TO DOLLARS

	//🟨 How to Round a number :-

	Math.round(2.2) //  2
	Math.round(2.6) //  3
	;((2095 + 799) * 0.1) / 100 // 2.894    //  inner (Calculate 1st)

	Math.round((2095 + 799) * 0.1) / 100 //  2.89  //  $DOLLARS

	var number = 3.7
	var roundedNumber = Math.round(number)
	console.log("Rounded Number: " + roundedNumber)

	//🟨 2 * 2 * 2
	var base = 2
	var exponent = 3
	var result = Math.pow(base, exponent)
	console.log(base + " raised to the power of " + exponent + " is " + result)

	//🟨 Square Root
	var number = 16
	var squareRoot = Math.sqrt(number)
	console.log("The Square root of " + number + " is " + squareRoot)

	//🟨 Random Number Generation
	var randomNum = Math.random()
	console.log("Random number between 0 and 1 is : " + randomNum)

	var randomInRange = Math.floor(Math.random() * 10) + 1
	console.log("Random Number between 1 and 10 : " + randomInRange)

	//🟨 Absolute Value
	var num = -5
	var absoluteValue = Math.abs(num)
	console.log("Absolute value of " + num + " is " + absoluteValue)

	// 🟨 MATH 🟨

	var randomNum = Math.random()
	console.log("Random Number : " + randomNum)

	var num = 5.7
	var roundedDown = Math.floor(num)
	console.log("Rounded Down: " + roundedDown)

	var num = 5.1
	var roundedUp = Math.ceil(num)
	console.log("Rounded Up: " + roundedUp)

	var num = 5.3
	var rounded = Math.round(num)
	console.log("Rounded: " + rounded)

	var maxNum = Math.max(10, 20, 30, 40)
	console.log("Maximum Number : " + maxNum)

	var minNum = Math.min(10, 20, 30, 40)
	console.log("Minimum Number : " + minNum)

	var base = 2
	var exponent = 3
	var result = Math.pow(base, exponent)
	console.log(base + " raised to the power of " + exponent + " is = " + result)

	var number = 16
	var squareRoot = Math.sqrt(number)
	console.log("Square root of " + number + " is = " + squareRoot)

	console.log("The value of PI is : " + Math.PI)
</script>