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## 1st grade

### Course: 1st grade>Unit 1

Lesson 2: Ones and tens

# Place value example: 25

Sal shows 25 as 2 tens and 5 ones. Created by Sal Khan.

## Want to join the conversation?

• does Sal split the numbers up so that people can understand what it really means?
(67 votes)
• Yes. To help give you intuition behind the number and place value of numbers.
(60 votes)
• So, how did we start grouping by 10's. It couldn't been something like binary, so why tens? Was it because we have 10 fingers?
Please answer in detail!
(22 votes)
• It is because we have ten fingers! ancient people would use the different parts of their bodies to count. They would start with their fingers, then toes, then limbs, then head.
(11 votes)
• Wait, so there's Place value example: 25, so where's Place value example: 24?
How does that Work?
(8 votes)
• If I am reading your question correctly, you are asking what the place value for 24 is, right?

If you had the number 134, it would go in like this:
Hundreds | Tens | Ones
--------1------------3--------4
Because there is 1 in the hundreds place, 3 in the tens place, and 4 in the ones place.

For 24 it would look like this:
Tens | Ones
---2-------4
Because there are 2 tens, and 4 ones.

Let me give you one more example. For the number 397:
Hundreds | Tens | Ones
------3------------9-------7

Here in the hundreds place we see 3. If 2 were there, the number would be 297 instead of 397. In the tens place there is the number 9. That number tells us to say eighty, fifty, thirty, or any other ty number. In this case, the nine in the tens place makes it 90. Finally in the ones place we have 7. This tells you what 0-9 number goes on the end of 397.

I hope this helped you!
(2 votes)
• what is the value of 3 in the number 36
(2 votes)
• Hi Eva!

The number 3 is in the tens place. 6 is in the ones place. Hope this helps!
(3 votes)
• What does it mean when Sal shows 25 as 2 tens and 5 ones.?:)
(2 votes)
• The number 25 can be thought of as 2 groups of ten items plus 5 groups of 1 item(s). If it was money, a quarter (25 cents) could be represented as 2 dimes (2 groups of ten) and 5 pennies (5 groups of 1).
(3 votes)
• what grade is this for because it is really easy for me but i still have not mastered all of it so should i finish it?
(2 votes)
• This is grades kindergarten through 2nd grade, also known as early math. If you want to find your grade, the scroll up, and click subject. If you put the arrow over math, then you'll find all the grades. Click your grade and start learning!
(2 votes)
• what is the 1's for place value in the number 300
(2 votes)
• 300 consists of 3 hundreds, 0 tens, and 0 ones.

0 ones = 0,
so the 0 in the ones place has a place value of 0.
(2 votes)
• is the metric system the new American measuring system? Because I know that all it is is tens and zeros to make uneducated peoples' lives simpler.
(2 votes)
• The USA officially uses the imperial system. However, the metric system is often used, even in the USA, because the units are easier to understand and work with.
(2 votes)
• Would 119 be the same as 1 hundred, 1 ten, and 9 ones or 11 tens and 9 ones?
(2 votes)
• Both of those have the same value and they both would be correct.
119 = 1 hundred, 1 ten, and 9 ones = 11 tens and 9 ones
(0 votes)
• why do we have to group them?
(0 votes)
• Grouping numbers helps you to be able to count easier. Instead of counting individual objects, you can just count the group. Does that make sense?
(5 votes)

## Video transcript

Voiceover:What I want to do in this video is think a little bit about what numbers really represent. Let's say someone were to write down the number 25. So what does this really mean? Well the five here, this is in the one's place so it literally represents five ones. And this two right over here, this is in the 10's place, so let me write that down. That's the 10's place, that's the one's place, so this represents two 10s. What do I mean by that? Well another way to write this is this two represents two 10s, just let me write that down. This is equal to two 10s plus five ones. Now what are two 10s? Well that's literally if you can imagine a 10 being a block of 10 things, so you could imagine if this was a 10 right over here. Let me copy and paste this, so copy. So this is going to be the same thing, this is going to be equal to, you have your two 10s, so one 10 and two tens, so you have your two 10s. So that's your two 10s right over there, that really represents 20 plus your five ones. Plus your five ones. Well if this is a one right over here, and I'm just representing it as kind of one vertical bar, five ones are going to look like, your going to have one, two, I think you see where this is going, three, four, and five. And so these are all different ways of representing the same quantity. 25 is two 10s and five ones. This two is in the 10's place, the five is in the one's place. So two 10s plus five ones, so you could then view it as two groups of 10 plus five ones right over here. And what's this going to be the same thing as? Well two groups of 10, this is the same thing as 20 and this over here is equal to five. So once again, all ways to represent 25. You can view this as two 10s plus five ones or you can view this as 20, let me write this down, 25 you could view because this two is two 10s that represents 20 plus the five ones.