JavaScript Basics Stephen Delaney sdelaney@skokielibrary.info

Review: Working With Numbers Doing math in JavaScript The random challenge

Types of Numbers Integers 10, -8, 2787382 Floating point numbers 3.14, -10.6454 Scientific notation 5.7e+4 => 57000

Is this a number? var greatNumber = ‘10’ *Introducing typeOf()

What are these for? += -= *= /= var score = 10 score += 7 17

What’s the difference between? parseInt() parseInt(10.6) 10 parseFloat() parseFloat(10.6) 10.6

What do these mean? NaN Not a Number DRY Don’t Repeat Yourself

What do these do? Math.round() Math.round(10.6)  11 Math.floor() Math.ceil() Math.ceil(10.6)  11

What does this do? Math.random() Floating number, from 0 (inclusive) to 1 (exclusive)

Challenge: Write the code to generate a random number between 1 and 10. Math.floor(Math.random() * 10) + 1

Questions?