Fundamentals 1: variables & numbers

Question 1

What is a variable?

Answer 1

“storage containers” for data in your code

Question 2

3 keywords to declare a variable

Answer 2

let
const
var

Question 3

Which of the three variable declarations should you avoid and why?

Answer 3

let and const are newer
var can cause unexpected output

Question 4

Identifying some naming conventions for variables in JS

Answer 4

use camelCase
no reserved words (keywords)
use english (for future posterity)
meaningful - they indicate what value is stored inside

Question 5

Naming conventions: what can variable names contain?

Answer 5

only letters
digits
symbols ($, _)

Question 6

What are operators, operands, and operations?

Answer 6

operands are the data acted upon by the operators

operators: mathematical symbol that indicate how data should be treated (x = / * etc)

operations: the calculation that happens

Question 7

Explain the difference between prefixing and postfixing increment/decrement operators

Answer 7

prefix - when increment/decrement operator comes before
++count
returns the count after crementing is applied

postfix - when increment/decrement operator comes after
count++
returns the final count before crementing is applied

still quite confused by this

Question 8

Unary vs binary operation?

Answer 8

unary - one operand
binary - two operands

Question 9

What will produce a NaN result?

Answer 9

computational error, incorrect or undefined mathematical operation

trying to perform any further operations on NaN will still yield NaN

Question 10

Which math operation with NaN will produce a result?

Answer 10

NaN * 0 = 1

Question 11

how to check if a value is NaN?

Answer 11

isNaN()

Question 12

What does it mean when we call javascript a dynamically typed language?

Answer 12

variables and data types are not bound to each other