courtesy Math Smart Junior
by Marcia Lerner

Adding and Subtracting Fractions

Tom ate his slice the way cats eat everything, cleanly and neatly, without getting so much as a smudge of tomato sauce on his whiskers.  Taylor ate his slice slowly.  Sondra put hers on a plate, carefully removing the crust, then cut the rest into tiny cheesy pieces that she ate with a fork.  Jennifer, however, grabbed up her slice and wolfed it down so fast that before anyone had noticed she was into her second piece. 
The cat and three kids had each had a slice of pizza, then Jennifer had grabbed another, so now the pizza was missing 5 pieces.

How many pieces of pizza are in the process of being eaten?  
5 pieces.

What fractional part of the pizza is being eaten?

5 parts out of a whole 8, so

Answer:

Five-eighths

If 5 pieces were eaten what fractional part of the pizza is left?

-

=

Three-eighths

*

Hint: The trick with adding and subtracting fractions is that you only subtract or add the top part of the fraction, which is called the numerator. The bottom part is called the denominator, and stays the same because the whole does not change, just the number of pieces taken or left changes.

How about if you combine what is left with what is being eaten?

or 1

=

+

** Remember you only add the numerators

"This is the best pizza I've ever had!" Jennifer said between big, happy mouthfuls.
"Delicious, yes, but I believe I've had quite enough to satisfy my appetite," Tom commented.
"Mmmm," Taylor nodded, "I hate to say it, but I'm feeling pretty good now, too."
"That was excellent," Sondra said, untucking the napkin she'd folded around her collar.
"Do you mean I can have the rest?" Jennifer cried, her eyes lighting up like the headlights on a car.  "Eyaaa!" She ate the remaining pizza.  Jennifer sat smiling on the floor, patting her tummy, "Excellent."