Introduction to addition

Let's think about what it means to add numbers.

So let's start with one.
One plus -- one plus one.

What is this going to be equal to?

One way to think about this is
we have one thing.

And I will -- that thing will be a purple circle.

So let me put that here.

So that's this 1 thing.

I'm just going to represent it with a purple circle.

And I'm going to add another 1 thing.

And since this is in blue,
I'll make that other circle.

I'll make that in blue as well.

So, let me put that right over here.

So, 1 plus 1. 1 plus 1.

How many total circles do I now have?

Well, I now have 2 circles.

I now have 2 circles.

1 plus 1 is equal to 2.

OK, you're saying, "All right, Sal, that makes sense."

Let's do this with larger numbers.

So let's say we want to know what equals--

and I'll put a question mark over here.
So, question mark.

What equals --

So something is equal to, let's say, 2, 2, 2 plus 3.

Something is equal to 2 plus 3.

What is this something going to be?

And I encourage you to pause the video
and think about it on your own.

Well, you can view this as,
I have 2 objects,

and then I am going to add
another 3 objects.

How many total objects would I have?

So you have your 2 objects,
which I'll use purple circles again.

So let me --

Let me, so we have 1 and 2 purple circles.

This is the 2 right over here.

And then to that,
we're going to add 3 more.

3 more circles.

And I'll represent those in blue,
because we wrote the 3 there in blue.

So that is 1, 2, and 3.

So how many total circles do we now have?

Well, we can count them.
We have 1,2,3,4,5.

In fact, let me count that.
1,2,3,4,5 circles.

So 2 plus 3

2 things plus another 3 things
are 5 things.

So our question mark over here
is equal to 5.

So, instead of writing the question mark

right over here, let me clear that out.

I could say 5 is equal to --

I could write down that 5
is equal to 2 plus 3.