By the time students arrive in third grade, the explicit teaching of place value is not reflected in the Common Core State Standards. In fact, place value is very much ignored by the Common Core for third grade math. In second grade, the students are explicitly taught place value to 1,000. It is not until grade 4 that students resume place value learning going up to 1,000,000. So what happens in third grade, you ask?
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Lots of review! The third grade math standards are extensive enough that taking time to explicitly teach or reteach place value is a hard thing to fit in. Most second graders do understand place value to 1,000 well enough that it is not a problem. But for those few that have still not mastered place value, some extra homework or free time practice is necessary.
The one place where the Common Core for Math in Grade 3 does explicitly say that students will use place value, is in rounding. Students must be able to round whole numbers to the nearest 10 and 100. I blogged recently about my experience with teaching rounding to third graders (especially since it is not taught in grades k-2...so it's their first time learning how to round). Let's take a look at rounding.
In the past I have used number lines and chants and rhymes. But I decided I needed something new and different to teach it since it seemed that students would eventually forget to round in the later part of the year. So I looked around on Teachers Pay Teachers and found this amazing resource by The Math Spot (read the blog post that explains it in detail!) called Rounding Without Rhymes.
|Rounding Without Rhymes|
|Rounding on the number line using a white board.|
Once the students understood the concept of rounding, we practiced on white boards. I would give them a number. Then they had to draw a number line with the preceding 10 and the next 10. Then they had to locate the middle number and place it. Then they place with an X the number they have to round on the number line. From there they determined which 10 it was closest to and circled it. We did the same procedure when rounding to the 100s. This task was more difficult because for many students that middle number was hard to get! With guidance, they eventually got the hang of it.
From that point, the students actually had to use rounding to get an estimate when adding multi digit numbers. This is not a skill that is used only once and forgotten! They will have to round in subtraction, multiplication and division. So to keep up the skill I am having them round a few times during math or during the day as sponge activities that take no longer than 5 minutes:
- stand up sit down: I say a number, then I say: stand up if you think the number rounds to __ or sit down if you think the number rounds to ___. This also gives me a quick visual check to see who's still not getting it.
- find your rounding partner: half the class gets a card that either has 10, 20, 30, 40, 50, 60, 70, 80 or 90. You can also do this with hundreds as well. Then the other half gets a card with a number between 0 - 100. When I give the signal, the class has to find a partner whose number will round to that 10.
- random call: Literally throughout the day I will just randomly say a number and the first person to round the number to the nearest 10 or 100 gets a class reward ticket. Hokey but it works!
|Rounding Card FREEBIE|
|Rounding cards with 10s and 100s|
To get you started with your students on rounding on a number line, I've included a FREEBIE! Rounding Cards. Print them, laminate them, then cut them. Use them on a document camera to demonstrate to your students the procedure for rounding on a number line. Included are cards for rounding to the nearest 10s, 100s and blank cards to make your own! Enjoy. Don't forget to let us know how you teach rounding by using the comments section. Also, don't forget to continue with the Math Tip Monday links. Happy rounding!