Adding Whole Numbers and Applications 1

Adding Whole Numbers and Applications 1

So we need to figure out what 46 plus 43 is.

Let me write it down again

and I'll write it like this: 46 plus 43.

What we do here is

we just first look at the ones place

We literally have 6 ones plus 3 ones

or you could say 6 and 3, and 6 plus 3 is just 9.

6 plus 3 is 9, so we have 9 ones.

And then you go to the tens place

and there's two ways to think about it.

You could view this as 4 plus 4 is equal to 8

but really, the reality of what we're doing

since we're operating in the tens place

this is really 40 plus 40 is equal to 80.

And we could do the same problem expanded out.

This is the same thing as 40 plus 6.

We've seen this before, right?

That's what 46 is.

And then 43 is the same thing as 40 plus 3.

We've expanded these out before.

And so when you add them

when you add a 6 plus a 3, you get a 9.

When you add a 40 plus a 40, you get an 80.

So you get 80 plus 9, which is 89.

And the whole reason why I did this is

I wanted to show you that

when you're adding 4's in the tens place

you're really adding 40's.

The fact that it's in the tens place represents--

or the fact that the 4 is in the tens place

shows that it represents 40.

The fact that the 8's there

shows that it represents 80.