-
Most of us are familiar with the equal
sign from our earliest days of arithmetic.
-
You might see something like 1 plus 1 is
equal to 2.
-
Now a lot of people might think when they
see
-
something like this that somehow equal
means give me the answer.
-
1 plus 1 is a problem, equal means give me
the answer, and 1 plus 1 is two.
-
That's not what equal actually means.
-
Equal is actually just trying to compare
two quantities.
-
When I write 1 plus 1 equals 2, that
literally
-
means, that what I have on the left hand
side
-
of the equal sign, is the exact same
quantity as
-
what I have on right hand side of the
equal sign.
-
I could have just as easily have written 2
is equal to 1 plus 1.
-
These two things are equal.
-
I could have written 2 is equal to 2.
-
This is a completely true statement, these
two things are equal.
-
I could have written 1 plus 1 is equal to
1 plus 1.
-
I could have written 1 plus 1 minus 1 is
equal to, is equal to 3 Minus 2.
-
These are both equal quantities.
-
What I have here on the left hand side,
this is, this is 1, 1 plus 1 minus
-
1 is 1, and this right over here is 1,
these are both equal quantities.
-
Now, I will introduce you to other ways of
comparing numbers.
-
These are, the equal sign is when I have
the exact same quantity on both sides.
-
Now we'll think about what we can do
-
when we have different quantities on both
sides.
-
So let's say I have the number 3, and
-
I have the number 1, and I wanna compare
them.
-
So clearly, 3 and 1 are not equal, in fact
I
-
can make that statement with a not equal
sign, so I
-
can say 3 does not equal 1, but let's say
I
-
wanna figure out which one is larger and
which one is smaller.
-
So, if I wanna have some symbol, where I
can compare them, where
-
I can tell, where I can, I can state which
of these is larger.
-
And the symbol for doing that is
-
the greater than symbol, the greater than
symbol.
-
This literally would be read as 3 is
greater than 1, 3 is a larger quantity.
-
And if you need, if you have trouble
remembering what this, that this
-
means greater than, the larger quantity,
the
-
larger quantities on the opening, the
larger
-
on the, the, the larger, I guess if you
could view this as some
-
type of an arrow or, I guess a shet, well,
some type of symbol.
-
Then this is the bigger side.
-
Here you have this little teeny tiny
point, and here you
-
have the big side so the larger quantity's
on the big side.
-
This would literally be read as 3 is
greater than, so let me write that down.
-
Greater than, 3 is greater than 1.
-
And once again, it just doesn't have to
-
be numbers like this, I could write an
expression.
-
I could write, I could write 1 plus 1 plus
1, is greater than,
-
is greater than, let's say, well just one
1 right over there.
-
This is making a comparison.
-
But what if we had things the other way
around?
-
What if I wanted to make a comparison
between 5, and let's say 19.
-
So now the greater than symbol wouldn't
apply,
-
it's not true that 5 is greater than 19.
-
I could say that 5 is not equal to 19,
-
so I could still make, I could still make
this
-
statement, but what if I wanted to make a
statement
-
about which one is larger and which one is
smaller?
-
Well if in plain English, I would wanna
say 5
-
is less than 19, so I would wanna say, let
-
me write that down, I wanna write 5 is
less
-
than, 5 is, is less than is less than 19.
-
That's what I wanna say, and so we just
have to think
-
of a mathematical notation for writing is,
for writing is less than.
-
Well if this is greater than it makes
complete
-
sense, and let's just swap it around,
let's make, once
-
again, the point point towards the smaller
quantity and the
-
big side of the symbol point to the larger
quantity.
-
So here 5 is a smaller quantity, so I'll
make the point point
-
there, and 19 is a larger quantity, so
I'll make it open like this.
-
And so this would be read as 5 is less
than 19, 5 is a smaller quantity than 19.
-
I could also write this as, I could write
1 plus 1 is less that 1 plus 1 plus 1.
-
It's just saying that this statement, this
quantity, 1
-
plus 1, is less than 1 plus 1 plus 1.