Operations with Rational Numbers

Any number that can be written in the form , where m and n

are integers and n 0, is called a

rational number

In other words, fractions….

Fractions are used when we need to identify part of a whole.

To combine Rational Numbers, you must have a …

COMMON DENOMINATOR

• The LCD is the smallest number that all the denominators divide into evenly.

2 and 3

Think of the LCD for the following pairs of numbers

LCD = 6

3 and 4 LCD = 12

2 and 7 LCD = 14

3 and 6 LCD = 6

For example:

1 + 1 = 3 4 12 12

X 4

X 4

4 + 3

X 3

X 3

= 7 12

For example:

2 + 1 = 3 5 15 15

X 5

X 5

10

+ 3

X 3

X 3

= 13 15

For example:

1 - 2 = 2 5 10 10

X 5

X 5

5 - 4

X 2

X 2

= 1 10

For example:

3 + 2 = 4 5 20 20

X 5

X 5

15

+ 8

X 4

X 4

= 23 20

Multiplying and Dividing Rational Numbers

To multiply Rational Numbers, multiply corresponding

numerators and denominators

For example:

3 4 5 7

=

12

35

1 4 3 5

=

4

15

1 2 3 3

=

2

9

For division:Flip the second RN and Multiply

15

5 27 3

= ?

5 3 7 2

= 14

5 24 7

=

5 7 4 2

=

358

See Sheets