Gr.3 M5 L10 & 11 Concept Development

Gr.3 M5 L10 & 11 Concept Development

Objective: Compare unit fractions with different-sized models representing the whole. 

Poll

Which fractional unit is greater, fourths or eighths.

• fourths

• eighths

Let's find out if you were correct. To the right, we have two wholes that are the same size. That's important when comparing fractions.

To compare those fractional units, the top whole has been divided into fourths (4 equal parts) and the bottom whole has been divided into eighths (8 equal parts)

To compare, let's focus on one fractional unit (part) from each whole. Notice that 1 fourth is larger than 1 eighth.

Multiple Choice

So let me ask you again, which fractional unit is greater fourths or eighths?

• fourths

• eighths

You may still be wondering, how is 1/4 greater than 1/8 when the denominator 8 is a bigger number than the denominator 4. Well, let's look at this with more understandable terms like PIZZA.

Let's say you ordered a pizza pie and you are home all alone. You don't have to share the pizza with anyone. You get the whole pie. That's one large part.

Multiple Choice

Now let's say a best friend comes over (now there are 2 people including yourself) and you want to share your pizza pie equally. Which image shows how to cut the pizza evenly.

Multiple Choice

Another friend swings over, now there are three of you. Which image shows how you would equally share the pizza now?

Multiple Choice

Finally, one last friend shows up. Now there are four of you. You still want to share equally. Which image shows how the pizza pie should be divided?

As more people came, the number of needed parts increased, the denominator got bigger, but the size of each part became smaller. Use this understanding to compare unit fractions.

Multiple Choice

Compare 1/4 O 1/5

Multiple Choice

Compare 1/8 O 1/5

Multiple Choice

Compare 1/9 O 1/9

Multiple Choice

Compare 1/9 O 1/2

Multiple Choice

Compare 4/8 O 1/2