Paper Plate Fractions - Math Manipulative

Help kids learn about fractions with paper plates by giving them something that's visual and hands on. You could also do this with a regular sheet of paper (square would be best) if you don't have any plates.

Instructable 342

• Paper Plates - mine had a blue design on them, but you can always flip them over and use the back
• Crayons - or something else to color with
• Scissors
• Marker
• Protractor (optional)

This step is great for getting the kids involved. My daughter is 3 1/2 so she's a bit young to really understand fractions, but she was very helpful in coloring the plates with me.

The first plate is the easiest because it is 1 whole plate. You don't really have to do one for this, but I think it's good for reference for the others.

The even fractions are the easiest because they are even cuts.

For 1/2, all you need to do is fold the plate in half and cut.

For 1/4, you do the same and then fold those halves in half.

You can just continue like this and go as small as you want. I only went to 1/8th.

To do the odd fractions I decided to do the math and use a protractor to get the best cuts.

So, if you want to do 1/3, you need to take a full circle (360 degrees), and divide it by 3. This gave me 120 degrees which I marked on the protractor. This gave me 1/3 and then I did another 120 degrees to get the other two pieces.

I did the same thing to get 1/6. 360 divided by 6, was 60 degree angles.

Now you can combine different fractions to see the different ways you can make 1 from fractions. Such as:

2/8 (or 1/8 + 1/8) + 1/4 + 1/2 = 1

2/4 (1/4 + 1/4) + 1/2 = 1

I also decided to do a rainbow plate with a variety of fractions in one, but doing each fraction a different color helps makes visualizing easier.

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You can mix up odd and even fractions but it can get a bit confusing. You could use this as a way to try to get older kids to figure out what fraction of the whole is still missing (5th photo above): 2/6 + 1/3 + 1/4 = ?*

* Remember, to figure out fraction equations, you need a common denominator, in this case it would be 12, so this equation would look like: 4/12 + 4/12 + 3/12 = 11/12 and if you took 1 - 11/12 you would find out you need 1/12 to finish that circle. You could actually go ahead and then cut out a plate so you have 1/12 size pieces.

For a little something extra, you can stack your fractions and see which ones are larger than each other. So while it might seem obvious, kids can see that even though 8 is a larger number than 2, 1/8 is actually much smaller than 1/2.

Honestly, this is a good lesson for anyone. At one point A&W tried to do a promotion with a 1/3 pounder to compete with McDonalds 1/4 pounder. Theirs was more burger for the same price (1/3 > 1/4), but people didn't understand because they thought 1/4 was more than 1/3 because 4 is more than 3. So people didn't want to pay the same price for what they thought was less of a burger.

You can actually use Tinkercad to practice with circular fractions by using the Sliced Cylinder shape in the Shape Generators menu.

To use this, you will need to know the degrees of the circle for each fraction, but it's really easy. All you have to do is divide 360 degrees by how many slices you want (because a full circle is 360 degrees).

So for 1/2, you want 2 slices, so you take 360/2 which is 180 degrees. This will give you 1/2 slices. You put this value in the Arc option.

For 1/3, you take 360/3 which gives you 120 degrees. Once you have the shape you want, you can just copy and paste as many as you need.

You can use the text option to label each slice.

Now match them up like you did with your paper plates.

Here is a cheat sheet to get you started:

• Full Circle = 360 degrees
• 1/2 = 180 degrees
• 1/3 = 120 degrees
• 1/4 = 90 degrees
• 1/5 = 72 degrees
• 1/6 = 60 degrees
• 1/8 = 45 degrees

Learn more about using 3D design to teach math with this handy Instructable.