Cynthia Lanius

Who Wants Pizza? - Part 4

Friday Ms. Martinez ordered pizza. The boys ate 2/5 of the pizza and the girls ate 1/2. Mike, the boy on the right, in the green shirt, said, "We ate 3/7 of the whole pizza."

Do you see what Mike did? Is he right?

Let's Explore

This green is 2/5 of the pizza.

         

This green is also 2/5 of the pizza.

                   

 


This orange is 1/2 of the pizza.

   

This orange is also 1/2 of the pizza.

                   


Let's add both parts...

                   


 
...and write the fraction of the pizza that the children ate together.

2

5
+ 1

2
= 4

10
+ 5

10
= 9

10
= green and orange parts

total number of parts

Something for You to Do

Directions:Use colored markers and the square grid paper to draw the fractions as we have above and add the following.

1. 1/5 + 1/5.

(a. 1/5) (b. 2/5) (c. 1/2) (d. 3/4) (e. 5/6)


2. 1/2 + 1/4.

(a. 1/5) (b. 2/5) (c. 1/2) (d. 3/4) (e. 5/6)


3. 1/3 + 1/6

(a. 1/5) (b. 2/5) (c. 1/2) (d. 3/4) (e. 5/6)


4. 1/2 + 1/3

(a. 1/5) (b. 2/5) (c. 1/2) (d. 3/4) (e. 5/6)


5. Challenge: Which of all the sums that you found above is the largest?

(a. 1/5) (b. 2/5) (c. 1/2) (d. 3/4) (e. 5/6)


How Did You Do? Click on "Get Score" below.

 

Score =

Correct answers:

Was Mike correct? Is 2/5 + 1/2 = 3/7?

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lanius@math.rice.edu