ADDING AND SUBTRACTING RATIONAL NUMBERS

ADDING AND SUBTRACTING FRACTIONS

when we are adding or subtracting fractions:

• like denominators

• unlike denominators

like denominators

keep denominator, add/subtract numerators

Multiple Choice

1/5 + 2/5

• 3/10

• 3/5

• 1/10

Multiple Choice

7/10 - 3/10

• 4/0

• 4/10

• 2/5

REMEMBER TO SIMPLIFY

ALWAYS

ADDING/SUBTRACTING WITH UNLIKE DENOMINATOR

METHOD 1

LEAST COMMON DENOMINATOR

METHOD 2

MULTIPLY DENOMINATORS AND NUMERATORS BEFORE ADDING

Multiple Choice

1/5 + 2/3

• 3/8

• 13/15

• 1/5

Multiple Choice

7/9 - 2/3

• 1/9

• 5/6

• 1/3

​Decimal numbers are also rational numbers

​

​You can use a number line to add, it's a different method.

​

Multiple Choice

1/5 + 2/5

• 3/10

• 3/5

• 2/25

Multiple Choice

1.5 + (-1.8)

• 0.3

• (-0.3)

• 3.3

• (-3.3)

Multiple Choice

3/8 + 1/8

• 1/2

• 4/8

• 4/16

• 1/4

Multiple Choice

(-2/9) - 5/9

• 7/9

• -3/9

• 3/9

• -7/9

Multiple Choice

-1.2 + 8.4

• 6.6

• -9.6

• 7.2

• 10

Multiple Choice

-4.9 + 14.2

• 4.9

• 9.3

• 14.2

• 19.1