Find the LCD
Adding Fractions
Word Problems
Simplify the Fraction
Subtracting Fractions
100

1/3 - 1/5

What is the LCD?

3: 3, 6, 9, 12, 15

5: 5, 10, 15

The LCD is 15

100

1/2 + 1/4

The denominators are related.


1/2 + 2/4

3/4

100

I want to bake a cake. I add 2/3 flour and 1/4 sugar. How much did I mix together?

The denominators are denomi-neighbors so I can multiply them by each other to get 12.

4/12 + 3/12 = 7/12

100

3/15

We can divide it by 3 to simplify it to 1/5

100

6/8 - 3/8

3/8

200

1/2 + 1/4

What is the LCD?

2: 2, 4

4: 4

The LCD is 4

200

1/6 + 2/3

The denominators are related so the common denominator is 6.

5/6

200

Jenny is building a tree house. She has 1/2 a yard of wood and cuts off 1/3. How much wood does she have left?

The denominators are denomi-neighbors so I can multiply them by each other to get a common denominator of 6.

3/6 + 2/6 = 1/6

200

4/6

We can divide it by 2 to simplify it to 2/3

200

7/9 - 5/9

2/9

300

1/5 - 1/6

What is the LCD?

5: 5, 10, 15, 20, 25, 30

6: 6, 12, 18, 24, 30

30 the is LCD

300

3/4 + 1/5

4: 4, 8, 12, 16, 20

5: 5, 10, 15, 20

15/20 + 4/20 = 9/20

300

I want to create a bow to tie my Christmas presents. I tied 4/5 blue ribbon and 2/3 red ribbon together. How much ribbon did I tie altogether?

5: 5, 10, 15

3: 3, 6, 9, 12, 15

The LCD is 15.

12/15 + 10/15 = 22/15

1 and 7/15 ribbon

300

12/15

We can divide it by 3 to simplify it to 4/5

300

1 2/7 - 2/7

1

400

3/9 + 4/6

What is the LCD?

9: 9, 18

6: 6, 12, 18

The LCD is 18

400

3/5 + 5/6

The denominators are number neighbors so we can multiply them times each other.

18/30 + 25/30

43/30

1 and 13/30


400

Mr.Frankum needed stuff to fill his aquarium. He filled 1/9 with sand and 1/6 with mulch. How much more mulch does he have than sand?

9: 9, 18

6: 6, 12, 18

The LCD is 18

3/18 - 2/18 = 1/18

400

6/12

We can divide it by 3 to get 2/4 and then divide it by 2 to get 1/2

Or you can see that 6 is half of 12 so it simplifies to 1/2

400

1 1/5 - 3/5

6/5 - 3/5

2/5

500

3/12 + 1/3

What is the LCD?

12: 12

3: 3, 6, 9, 12

The LCD is 12

500

3/4 + 1/3

The denominators are denomi-neighbors so I can multiply them by each other to get an LCD of 12.

9/12 + 4/12 = 13/12

1 and 1/12

500

Mrs.Armstrong wants to put christmas lights around her tree. She put 5/8 yards of white lights and 3/4 yards of red lights. How many yards of red lights does she have than white lights?

The denominators are related so the LCD is 8. I only need to change one fraction.

6/8 + 5/8 = 1/8

500

15/35

They both end in a 5 so it can be simplified by 5.

It simplifies to 3/7

500

2 1/6 - 1 5/6

13/6 - 11/6

2/6

It can be simplified to be 1/3

M
e
n
u