INTRODUCTION TO FRACTIONS


Fractions are expressed as one number over another number, like this:



The number on the top is called the numerator and the number on the bottom is called the denominator.

EXAMPLE:

When you think of a fraction, think of a PIZZA!!

Suppose a pizza is cut evenly into the number of pieces in the DENOMINATOR. If the number of pieces YOU get is the NUMERATOR, the fraction of the pizza you get is:



Adding and taking away (subtracting) fractions can be pictured using slices of pizza. For example:





Multiplying fractions means cutting a portion into smaller portions. For example:



Unit 1 show you how to do this multiplication.

Dividing fractions means determining how many smaller pieces there are in a larger piece. For example:



This means there are 2 one-fourth pieces of pizza in a half pizza.

Unit 4 shows you how to do this division.

Unit 12 will introduce you to decimals.

Here's another way to look at fractions. Imagine that each of these lines is a board and you want to cut it into halves, thirds, fourths, sixths, and fifths. Here is what those board fractions look like:

one whole board!!
1/2 board 1/2 board
1/4 board 1/4 board 1/4 board 1/4 board
1/3 board1/3 board 1/3 board
1/6 board1/6 board1/6 board 1/6 board1/6 board1/6 board
1/5 board1/5 board1/5 board1/5 board 1/5 board


Notice that the 2 1/4th boards add up to a half board and that the 2 1/6 boards add up to a 1/3 board.

This means that 2/4=1/2 and 2/6=1/3. (We will investigate this more in unit 9.)


So now, let's begin our drills!