Ruby Programming Tutorial - 3 - Math and Variables Video Lecture - Introduction

alright guys welcome to your third Ruby
tutorial and in this lesson I want to
talk about the math functions in Ruby
and maybe something else if we have time
so you already remember from the first
tutorial that Ruby can do some simple
math calculations like adding numbers so
if we give something like 4 plus 9 and
hit enter it's going to give us the
answer of 13 it can also subtract like
32 minus 1414 let me go ahead and type
that properly it gives us the answer of
18 now any time you want to multiply two
numbers in real B you have to use the
asterisks on your keyboard now the
asterisks is a little symbol above the
eight on your keyboard so 4 times 6
would be 4 Astrix 6 which is 24 now
Division is a little bit different
anytime you want to divide such as 9
divided by 3 you need to use the front
slash go ahead and hit enter and you
have to read now that's fine and all but
the vision gets a little bit tricky say
we give us something like 13 divided by
4 now 13 divided by 4 is 3 point 2 5
however if we go ahead and hit enter we
get 3 that's interesting it didn't give
us a remainder it didn't give us a
decimal now the reason for this is
pretty weird it gave us the number 3
because you give ruby or ruby gives you
an answer depending on how you ask the
question now since you asked it a
question with whole numbers the whole
number 13 and the whole number 4 that's
why it thinks that you want a whole
number is your answer and that's why I
gave you a whole number rounded to the
nearest whole number and not 3 point 2 5
or 3 and 1/4 or anything like that so if
you want a number with a decimal point
you have to ask it with decimal points
is the question such as 13 point O
divided by 4.0 now when you ask it like
this it gives you the answer three point
two five and we'll talk about different
data types later on but these are called
intents are basically whole numbers and
floats FL Oh 80 is basically a number
with a decimal point so just remember
whenever you
into answer you have to ask an inch
whenever you want flow s answer you have
to ask it in floats so now with that
being said the next thing I want to talk
to you guys about is variables now a
variable if you remember from elementary
school is basically a placeholder
for something else so if I wrote a
variable like x equals 15 and I go ahead
and hit enter this is how you write
variables in Ruby go ahead and hit enter
and now any time you write X it equals
15 so basically instead of writing 15 we
can just use the letter X and equations
in the example of X plus 10 and it
basically knows what we're trying to say
is whenever we use X plus 10 we treat it
as 15 plus 10 hit enter and gives us the
answer of 25 so basically to create a
variable just write the variable name
which is I'll just say it's Y hit the
equal sign and give it a value which can
be something like 69 now go ahead and
hit enter now what it does is it stores
the value of 69 into the letter Y so now
every time we use the letter Y it treats
it is 69 so Y plus 20 equals 69 plus 20
that's what it views it as and whenever
we hit enter gives us the answer of 89
so basically just remember that's how
you create variables in a variable is a
placeholder for something else so there
you go there's your very simple tutorial
on math and variables and if you don't
understand any of this stuff again I
need a stress ask me on my forum tnb
forum comm I'm going to be moving a
little fast with this so if I'm moving
too fast just either leave me a comment
or let me know but anyways thank you
guys for watching don't forget to
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see you guys later