(upbeat music) - Hello, everyone, and 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.

We got one.

Let's see what it says.

"Ms. Post, my big sister is about to celebrate her quince."

Congratulations.

"Lots of people have been invited.

The caterer is planning for dinner and thinks about 87 people are coming so far.

Should we round up?"

This is a great question and yes, you should definitely round up because you don't wanna run out of food!

But let me show you mathematically why you should round up.

Now remember, rounding is a way to make a big number, simpler and caterers usually don't want an exact number like 87, but since we can't ever know for sure how many people will come to an event, we estimate and round.

So let's review rounding whole numbers.

I have it all right here for us.

When you're rounding a whole number, the first thing you want to do is mark your place.

So either your ones, or your tens, or your hundreds, whatever number you're rounding to.

After you've marked your place, look next door.

When you look next door, the number to the right, if that number is four or less then let your number rest.

But if the number is five or more, you're gonna let your number soar.

Now, two more things to remember, numbers in the front stay the same, numbers behind, zero's their name.

Okay, so for the example on the postcard, we have 87 people coming.

Let's round to the nearest 10.

So that means our 87 is either going down to 80 or up to 90.

So first we're gonna mark our place and we're rounding to the tens, so let's mark our eight.

Then we're gonna look next door, and when I look next door, there's a seven.

So down on the number line, seven falls right here in the five or more range so we are going to let our 87 soar up to be a 90.

The eight soars to a nine and remember, numbers behind, zero's their name, so the seven becomes a zero.

Let's think about another scenario.

Let's say that you were at the grocery store helping your parent shop.

Every time something gets put into the shopping cart, you add its cost to the total.

When you're finished, your parent asks you about how much the bill should be, and your total is $135.74.

Let's practice rounding again to the nearest ten.

First, we're gonna mark our place, so we're gonna mark our tens place, which with this number is the three.

Second step, we look next door.

When I look next door to my three, I see a five.

Now five falls right here on our number line.

Five is in the five or more range so we are going to let our three soar up to be a four.

Now remember, numbers in the front stay the same so our one is going to stay a one.

The number behind, zero's their name, so the five, seven, and four all go to zero.

So you can tell your parent that the bill should be about $140.

Being able to estimate and round is a very important skill.

If you were at the grocery store that day and your bill came to $190, you would know that something was priced wrong and you could double check for an error.

I want to challenge you with this.

Ask an adult friend or a family member to take you on a trip to the grocery store.

Figure out how much your bill should be to the nearest tens place, then see how close your estimate is when you check out.

Thank you so much for the postcard.

I hope today's lesson helped you think about times when rounding is important.

Have a great rest of the day.

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

There's nothing you can't do if you put your mind to it.

I'll see you soon.