ADDING AND SUBTRACTING FRACTIONS (2) GRADE 3

Hello, How are you doing? Today, we are going to start a new lesson on Adding and Subtracting Fractions.

Numerator and Denominator Numerator – The number above the bar in a fraction. Denominator – The number below the bar in a fraction. 4 numerator 5 denominator

Subtracting Fractions Subtracting Fractions – Finding the difference of the fractions having like denominators. Example – To subtract 6/11 – 2/11

Difference The answer in a subtraction problem is termed as difference. Example – To subtract 10/15 – 2/15

Subtraction Fractions : Model To Subtract 7/15 - 1/15 Step 1:Use seven 1/15 fraction pieces to show 7/15 Step 2: Take away one 1/15 fraction piece. Step 3: Count the number of remaining 1/15 fraction pieces to find the difference.

7/15 – 1/15 = 6/15 1/15 1/5 1/15

Difference of fractions 8/12 – 4/12 Step 1: Put the fractions in an order. 8/12 – 4/12 Step 2: Subtract the numerators 8 – 4 = 4 Step 3: Write the difference over the common denominator 8/12 – 4/12 = 4/12 Step 4: Write the fraction in simplest form 8/12 – 4/12 = 1/3

Find the difference of 11/18 – 2/18 Solution : 11/18 – 2/18 = (11 – 2)/18 = 9/18 = 1/2

Which is not possible? a) 1/15 – 4/15 b) 8/17 – 15/17 c) Both are possible d) Both are not possible

Important Tips To subtract the fractions, subtract the numerators and write the difference over the common denominator. The smaller fraction is subtracted from the greater fraction.

How many fraction models will you need to show 5/9 – 4/9? Which ones will you need? Answer – 5 fraction models of 1/9 strips are required

Practice Problems

Which is closer to 1? a) 5/18 – 1/18 b) 9/18 – 6/18 c) 8/18 – 4/18 d) 18/18 – 1/18

Dab has 3/5 cup of mixed juice. He drank 1/5 cup of juice. How much juice is left?

Find the value of n 8/12 - 2/12 = n a) 1/2 b) 1/5 c) 1/6 d) None of the above

Which is greater? a) 8/14 – 4/14 b) 3/14 + 1/14 c) 7/14 – 3/14 d) 1/14 + 4/14

ASSESSMENT

1.What number sentence is modeled by fraction models for 3/5 with 1 strip crossed out? a) 3/5 -3/5 b) 3/5 – 1/5 c) 3/5 – 2/5 d) None of the above

2.Compare using 2/10  4/10 - 1/10

3.Subtract 4/11 from 9/11.

4.A box of beads fell on the floor. 7/12 of crayons fell out. What fraction of crayons are still in the box?

5.May has a greatest book collection. 5/14 collection is from Europe and 3/14 collection is from Russia. How much more of the collection is from Europe than from Russia?

6.A Cook needs 3/4 cup of cocoa powder and 2/4 cup of grated cheese for a special crunchy cake. How much less grated cheese is required than cocoa powder?

7.Lorrie found 8/16 of Pineapple Pie in a box. He ate 7/16 of pie. What fraction of the pie was left?

8.Find the missing number. 8/14 – 2/14= /7

9.Subtract the following. 1/16 1/16 1/16 1/16 1/16 1/16 1/16 1/16

10.Wilson ran 5/20 of a mile. Rock ran 3/20 of a mile. In the simplest form, how much farther did Wilson ran more than Rock?

Recap Numerator and Denominator Difference Subtract Fractions with like denominators Using Model to find the difference Important Tips Solved Examples Assessment

Well Done! Now you can practice worksheets on the Lesson.