Adding, subtracting, multiplying, and dividing fractions Amie Schneider Teacher page

Adding Fractions- Step 1- Make sure both the fractions have a common denominator. Example- 1/3 + 1/6 = ? ^Not the same^ Find a common denominator Multiply 1/3 by 2 on the top and bottom (2)(1) = 2 (2)(3) = 6 New fraction = 2/6

Adding Fractions- Step 2- Now having common denominators we can add the fractions Only add the numerators (top) 2/6 + 1/6 = 2 + 1 = 3 Denominator remains 6 Answer 3/6

Adding Fractions- Step 3- If possible simplify your answer = Does 3/6 equal something else? Find the greatest common factor 3/6 = 1/2 because the GCF was 3 3 ÷ 3 = 1 and 6 ÷ 3 = 2 =

Subtracting Fractions- Step 1- Make sure the denominator are the same Example- 1/2 - 1/10 = ? ^Not the same^ Find a common denominator Multiply 1/2 by 5 (1)(5) = 5 (2)(5) = 10 New fraction = 5/10

Subtracting Fractions- Step 2- Now that we have common denominators we can subtract! Only subtract the numerators. Example- 5/10 – 1/10 = ? 5 – 1 = 4 Denominator remains 10 Answer – 4/10

Subtracting Fractions- Step 3- If possible simplify your answer. Does 4/10 equal something else? Find the greatest common factor 4/10 = 2/5 because the GCF is 2 4 ÷ 2 = 2 and 10 ÷ 2 = 5

Multiplying Fractions- Step 1- Multiply the numerators Example- 1/2 x 2/5 = ? 1 x 2 = 2 *This time we don’t need a common denominator!

Multiplying Fractions- Step 2- Multiply the denominators Example- 1/2 x 2/5 = ? 2 x 5 = 10

Multiplying Fractions- Step 3- If possible simplify your answer Answer – 2/10 Find the greatest common factor 2/10 = 1/5 because the GCF is 2 2 ÷ 2 = 1 and 10 ÷ 2 = 5

Dividing Fractions- Step 1- “Skip, Change, Flip” Don’t change the first fraction – Skip Change the ÷ to a x - Change Flip the second fraction upside down (the reciprocal)- Flip Example- 1/3 ÷ 2/4 becomes 1/3 x 4/2

Dividing Fractions- Step 2- Answer- 4/6 Multiply the numerators 1 x 4 = 4 Multiply the denominators 3 x 2 = 6 Answer- 4/6

Dividing Fractions- Step 3- If possible simplify your answer Find greatest common factor Answer- 4/6 4/6 = 2/3 because the GCF is 2 4 ÷ 2 = 2 and 6 ÷ 2 = 3

Now lets see what you have learned……

#1-What is 2/5 + 1/5? 3/5 3/10 2/25 1/5

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#2-What is 3/4 - 4/6 ? 7/10 1/12 12/24 1/2

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#3-What is 1/2 x 2/3? 3/5 1/6 1/3 2/5

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#4-What is 1/4 + 2/3? 11/12 3/7 2/12 3/12

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#5- What is 1/3 ÷ 2/3? 1/3 2/6 1/2 2/3

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#6- What is 2/5 – 1/3? 2/15 1/15 3/8 1/2

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#7- What is 3/4 x 1/8? 3/32 2/4 4/12 3/12

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#8- What is 1/8 ÷ 2/3? 2/24 2/16 3/16 1/5

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