Arithmetic Operators

Quick reference

• 00:04 In this video I wanna talk about arithmetic operators, math operators.
• 00:09 So we've talked a little bit about math in the last video but
• 00:12 there's a bit more to talk about.
• 00:13 So here are the main math operators, and
• 00:16 they're exactly like you'd think they would be.
• 00:18 Let's go ahead and delete this.
• 00:20 We've got addition, subtraction, multiplication,
• 00:23 division, exponents, and then we've got the modulus.
• 00:27 We talked about that a little bit in the last video.
• 00:29 And then we have these two that you may not have heard of, increment and
• 00:32 decrement.
• 00:33 So these all act, like I said, exactly like you'd think.
• 00:37 This adds things.
• 00:38 This subtracts things, multiplies, divides.
• 00:40 This does exponents.
• 00:41 But these last three may not be familiar to you.
• 00:43 We kind of talked about modulus already in the last video.
• 00:46 I'll run through these very quickly and then we'll talk about these last three.
• 00:49 So, lets do a little bit of math here.
• 00:50 We've got our script tags.
• 00:52 We can do just very basic math, go to document.right,
• 00:57 and inside here we can go 2 + 2 and that,
• 01:01 hit reload, boom, we got 4, 2- 2 is 0.
• 01:05 We could go 2 exponent 2, 2 to the second power, which is 4.
• 01:11 Or 2 to the 8th power which is 256.
• 01:17 We can do division, all the good stuff.
• 01:21 Now we can also assign variable names.
• 01:23 We can go var x equals 1, let's say 2.
• 01:28 And var y equals 3.
• 01:31 And in here we can go x plus y.
• 01:35 So you don't have to actually use numbers, you can use variables too.
• 01:37 So 2 plus 3, that's gonna be 5 and all that good stuff.
• 01:41 So, that's very basic.
• 01:42 Next, let's talk about the increment and the decrement.
• 01:45 I'm not even sure with decrement is a word, it sounds a little funny.
• 01:48 But let's go ahead and, let's go var x = 10.
• 01:54 And x is a horrible variable name but I'm just using it 'cause it's quick and easy.
• 01:58 Now we can go x++, that's increment.
• 02:02 And now if we just write out x, what do you think the answer's gonna be?
• 02:06 So we're taking 10, we're incrementing it by 1.
• 02:09 So it should be 11.
• 02:10 Same thing, we can do decrement to decrease it and it's gonna be 9.
• 02:17 So, this is actually very useful.
• 02:19 You'll use this all the time for a bunch of different things.
• 02:21 And so those are your basic math operators.
• 02:24 Now I wanna spend just a minute talking about order of operations.
• 02:27 Now this is something you talk about in grade school math and
• 02:29 you probably forgot about it.
• 02:30 But order of operations is important.
• 02:32 So if we go var x equals 8 plus 2 times 3 and
• 02:38 then we write out x, what's the answer gonna be?
• 02:45 Is it gonna be 8 plus 2, which is 10 times 3 which is 30?
• 02:48 Or is it gonna be 2 times 3 which is 6 plus 8 which is, what, 14?
• 02:53 Let's see, the answer is 14.
• 02:56 Because in the math order of operations,
• 02:59 multiplication takes precedence over addition.
• 03:02 So you always do multiplication first.
• 03:04 Likewise, you do division before you do addition or subtraction.
• 03:07 So you may have to sort of brush up on your order of precedence,
• 03:10 order of operations.
• 03:11 You could look up on Google if you need to remember that.
• 03:13 You can change this, you don't have to use the order operations,
• 03:16 you can sort of over ride this by using parenthesis.
• 03:20 So whatever is inside the parenthesis gets done first,
• 03:23 that's also an order of operations rule.
• 03:25 So now the answer's gonna be 10 x 3, we save this should be 30, and it is.
• 03:31 So that is math.
• 03:32 Math is very simple, but you are going to use it a lot whenever you use JavaScript.
• 03:35 So that's math and the next video we'll look at comparison and logic operators.

Lesson notes are only available for subscribers.