Arithmetic Operators

Quick reference

• 00:04 In this video, I want to talk about math operators, or arithmetic operators.
• 00:08 So, it doesn't really matter what programming language you are using,
• 00:11 you're always going to need to do math.
• 00:13 And Ruby makes math really easy,
• 00:15 most programming languages do math pretty easily, but Ruby's especially easy.
• 00:19 And so, I'm just going to dive in and start showing you this stuff.
• 00:21 So let's comment, let's say math operators.
• 00:25 So anytime you want to do math you use an operator.
• 00:28 And an operator is just in this case plus sign,minus sign,
• 00:33 multiplication, division, exponents and the modulus.
• 00:38 And if you're not familiar with the modulus,
• 00:40 I'll show you that in just a minute.
• 00:48 So to do math in Ruby, is very simple I'll just put puts, and let's go 2 plus 5.
• 00:55 Now the first thing you'll notice is the numbers that I used I didn't put them
• 00:59 in quotation marks.
• 01:00 Up here when we output a string to the screen we use quotation marks, but
• 01:04 a number is not a string they're two very different things.
• 01:07 So you don't use quotation marks.
• 01:09 We save this, come down here, we're in our file, we get 7, 5 + 2.
• 01:15 And it's really just that easy to do math with Ruby.
• 01:18 We can switch this around and save, 5 minus 2, save it, run it and we get 3.
• 01:25 Likewise, multiplication 5 times 2, 10.
• 01:30 And if we change this around, 10 divided by 2 is going to be what?
• 01:34 5.
• 01:35 There we go. Exponents, do you remember exponents back
• 01:39 from grade school 4 to the 2nd power is going to be what?
• 01:42 16.
• 01:44 And the modulus might be something you're not familiar with, but it's pretty useful.
• 01:48 A modulus finds the remainder.
• 01:50 So remember in long division back in fourth grade math,
• 01:53 where if you divide something by another thing and there was something leftover.
• 01:58 So for instance, say 10 divided by 3.
• 02:02 Well 3 goes into 10 three times with 1 leftover.
• 02:05 So a modulus would return 1, it returns the remainder.
• 02:09 So if we save this and run the program, we get 1.
• 02:13 If we change this to two 10 is divided by 2 five times with 0 leftover or
• 02:18 0 remainder.
• 02:19 So if we run this we'll get 0.
• 02:22 So those are math operators, very, very easy, very, very useful.
• 02:25 And here is something that's kind of interesting about Ruby, and
• 02:28 not all programming languages work like this, but this is actually really cool.
• 02:31 So if we have a string and I'm just going to type in what's my name John Elder
• 02:36 and we go times to what do you think's going to happen here?
• 02:40 Normally you would get an error with a normal programming language.
• 02:42 But in Ruby, it multiplies the string times 2 and you get John Elder,
• 02:46 John Elder.
• 02:47 Now this is kind of useful because we can also do weird things like, is cool.
• 02:54 Save this and run it.
• 02:56 We get John Elder is cool.
• 02:58 It adds these two things together.
• 03:01 That's the sort of interesting thing about math and
• 03:03 math operators with Ruby that's maybe not the same with other programming languages.
• 03:07 Some programming languages will do this, but a lot of them won't.
• 03:10 So those are math operators, very cool.
• 03:12 In the next video, we're going to look at floats and integers.

Lesson notes are only available for subscribers.