Place Value

Shodor > Interactivate > Discussions > Place Value

Mentor: Do you remember using "ten-sticks" or "base ten blocks" in kindergarten?

Student: Yes, but I thought we were talking about place value. What do ten-sticks have to do with place value?

Mentor: Ten-sticks actually have a lot to do with place value. Let's look at an example. What does the 2 in the number 23 represent?

Student: It represents twenty.

Mentor: Right. And what would it look like if we used ten-sticks, or base 10 blocks, to make a representation of this number?

Student: It would have two sticks of ten and 3 individual cubes.

Mentor: Exactly. We could also think of it as 2 tens and 3 ones, couldn't we? Are you starting to see how this connects to place value?

Student: Yes, but we don't use ten-sticks anymore.

Mentor: Right, now we try to keep all of that information in our head. We write numbers in expanded form instead of building them with base ten blocks. Do you remember what that means?

Student: It's when you write 20 + 3 to show 23.

Mentor: Exactly. That helps us see each number's place value. Look at the 2. It's not just a 2, is it?

Student: No, it's 20.

Mentor: How do you know?

Student: Because it comes before the 3.

Mentor: It does come before the three, but the most important thing about it that tells us that it's actually 20 and not 2 is that it's in the tens place. That means that we can put any number in the second place like we did with the 2, and it means 2 tens instead of 2 ones. Think about a different example. What does the 5 mean in the number 523?

Student: It means 500.

Mentor: How do you know?

Student: Because the 5 is in the hundreds spot.

Mentor: Exactly. That's what people are talking about when they say "place value". Do you think you understand now?

Student: Yes. You can move a number to a different place and it stands for tens, hundreds, or even thousands, right?

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