(upbeat music) - Hello everyone, good morning, it's so good to be with you this morning, let's check the mail and see if there's a postcard for Ms. Post.

Yay I got one.

I just love getting mail from students in Arkansas.

Okay this sounds interesting let's read it, Ms. Post.

"I was thinking about how many French fries we eat at school."

I love French fries.

"And I have a math problem for you.

Ms. Joanne works in our cafeteria, and she says that every lunch tray has about 15 French fries on it, if there are 26 students in my fourth grade class, how many French fries does Ms. Joanne make for our class?"

This is a great question.

And I can think of three different ways that we could solve this problem.

Now, the longest way would be to add 15 French fries, 26 times.

Okay 15 one time, two times, three times.

I don't think we wanna write this 26 times do we?

That's a lot of adding, let's try something faster.

Did you know that multiplication is just a way to add repeatedly?

Multiplication is like a shortcut for adding groups, and in this problem, we're talking about 26 groups of 15 French fries.

So, the first way that we could multiply 26 times 15 is the traditional way.

Now this is probably the way that your teacher or other adults that you know learned how to multiply.

This is also the way that I learned to multiply when I was in elementary school.

26, times 15.

So first we take the five and we're gonna multiply it times the six, five times six is 30, the zero comes down, and the three carries.

Then we multiply the five times the two, five times two is 10, but I have to add that three.

And that gives me, 13.

Now because we've moved over to the tens place we fill in with a zero.

Now we do the one, and it's gonna multiply times the six and the two, one time six is six, and one times two is two.

Now we have our two partial products and we're gonna add them together.

Zero plus zero is still zero, three plus six is nine, and one plus two, is three, that's 390 French fries.

Okay another way that we can multiply is with a box that shows us multiplication like area.

We were doing 26 times 15, so I'm gonna split or decompose the 26, into a 20 and a six at the top.

Okay now we will decompose the 15 into a 10 and a five along the right side.

Now I drew this box to scale with the numbers that we're using, but you can always draw a very simple box with four spots for your partial products.

Now we multiply to fill in the four boxes.

20 times 10 gives us 200.

Six times 10 gives us 60.

20 times five is 100.

And six times five is 30.

And now we just add up all those partial products.

200 plus 100 is 300, 60 plus 30 is 90.

Combine your partial products, and we have 390.

Thank you for the postcard, can you believe that one class of fourth graders would need about 400 French fries?

And that was only for one class.

Well I hope today's lesson helped you think about different approaches to multiplication, and I hope you have a great rest of the day.

Remember keep a positive mindset, grow every day by reading and asking questions.

And remember there's nothing you can't do if you put your mind to it I'll see you soon.

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