copyright©amberpasillas2010 Add and Subtract Fractions copyright©amberpasillas2010

3 4 Parts of a Fraction = the number of parts Add and Subtract Fractions Parts of a Fraction 3 = the number of parts 4 = the total number of parts that equal a whole copyright©amberpasillas2010

3 4 Parts of a Fraction = numerator = denominator Add and Subtract Fractions Parts of a Fraction 3 = numerator 4 = denominator copyright©amberpasillas2010

Add and Subtract Fractions A Common Multiple is a number that is a multiple of two or more numbers. Some multiples of 3 & 6 6, 12, 18, 24, 30, 36, 42 copyright©amberpasillas2010

Add and Subtract Fractions The LCM is the smallest multiple that two numbers have in common. 5 = 5, 10, 15, 20, 25, 30 6 = 6, 12, 18, 24, 30, 36 copyright©amberpasillas2010

To Add or Subtract Fractions With Unlike Denominators Add and Subtract Fractions To Add or Subtract Fractions With Unlike Denominators List the multiples of each denominator to find the LCM. 1 5 = 5, 10, 15, 20, 25, 30 1 + 10 = 10, 20, 30, 40, 50 copyright©amberpasillas2010

To Add or Subtract Fractions With Unlike Denominators Add and Subtract Fractions To Add or Subtract Fractions With Unlike Denominators Compare your lists. Which multiples do 5 and 10 have in common? 1 5 = 5, 10, 15, 20, 25, 30 1 + 10 = 10, 20, 30, 40, 50 copyright©amberpasillas2010

To Add or Subtract Fractions With Unlike Denominators Add and Subtract Fractions To Add or Subtract Fractions With Unlike Denominators Use the lowest common multiple as the denominator. 1 5 = 5, 10, 15, 20, 25, 30 1 + 10 = 10, 20, 30, 40, 50 copyright©amberpasillas2010

To Add or Subtract Fractions With Unlike Denominators Add and Subtract Fractions To Add or Subtract Fractions With Unlike Denominators This number is also called the least common denominator. 1 5 = 5, 10, 15, 20, 25, 30 1 + 10 = 10, 20, 30, 40, 50 copyright©amberpasillas2010

Add and Subtract Fractions SHORTCUT: Check to see if the smaller denominator divides evenly into the larger denominator. If it does, use the larger denominator for your LCD or LCM. 1 5 will divide evenly into 10, so 10 is your denominator. 5 1 + 10 copyright©amberpasillas2010

1 5 10 1 + 10 10 Add and Subtract Fractions Rewrite the fractions using the least common denominator or least common multiple. 1 5 10 1 + 10 10 copyright©amberpasillas2010

Add and Subtract Fractions Find the equivalent fractions for 1/5 & 1/10 with 10 as the denominator. You know that 1/10 is equal to 1/10 so Put a 1 over the Denominator of 10. 1 5 10 1 1 + 10 10 copyright©amberpasillas2010

Add and Subtract Fractions Find the equivalent fractions for 1/5 & 1/10 with 10 as the denominator. To find the top number, ask yourself what do you multiply the 5 by to get 10. 1 5 10 1 1 + 10 10 copyright©amberpasillas2010

Add and Subtract Fractions Find the equivalent fractions for 1/5 & 1/10 with 10 as the denominator. 2 Since you are looking for the equivalent fraction you know the numerator must also be multiplied by 2. 1 x 2 = 5 10 x 2 1 1 + 10 10 copyright©amberpasillas2010

2 1 5 10 1 1 + 10 10 Now just add the numerators. x 2 = x 2 Add and Subtract Fractions Now just add the numerators. Remember when adding fractions you never add the denominators. 2 1 x 2 = 5 10 x 2 1 1 + 10 10 3 10 copyright©amberpasillas2010

Add and Subtract Fractions Identity Property states that any number multiplied by one equals itself This is useful to know so you can find a common denominator for adding and subtracting fractions.

1 2 8 1 + 8 8 Use the short cut to find the Least Common Denominator Add and Subtract Fractions Use the short cut to find the Least Common Denominator (LCD). 1 2 8 1 + 8 8 copyright©amberpasillas2010

1 2 8 1 + 8 8 x 4 = x 1 = Now find the equivalent fractions for Add and Subtract Fractions Now find the equivalent fractions for 1/2 & 1/8. 1 2 8 x 4 = 1 + 8 x 1 = 8 Ask what do you multiply 2 by to get 8 and what do you multiply 8 by to get 8. copyright©amberpasillas2010

1 4 2 8 1 + 8 8 x 4 = x 4 = x 1 = Since you are writing equivalent Add and Subtract Fractions Since you are writing equivalent fractions, now multiply the numerator by the same number you did on the denominator. 1 4 x 4 = 2 8 x 4 = 1 + 8 x 1 = 8 copyright©amberpasillas2010

1 4 2 8 1 1 + 8 8 x 4 = x 4 = x 1 = x 1 = Since you are Add and Subtract Fractions Since you are writing equivalent fractions, now multiply the numerator by the same number you did on the denominator. 1 4 x 4 = 2 8 x 4 = 1 1 x 1 = + 8 x 1 = 8 copyright©amberpasillas2010

1 4 2 8 1 1 + 8 8 5 8 x 4 = x 4 = x 1 = x 1 = Now add numerators. Add and Subtract Fractions Now add numerators. The denominator stays the same. 1 4 x 4 = 2 8 x 4 = 1 1 x 1 = + 8 x 1 = 8 5 8 copyright©amberpasillas2010

2 5 15 1 + 3 15 Find the least least common multiple for 5 Add and Subtract Fractions Find the least least common multiple for 5 and 3. Write it as your denominator 2 5 15 1 + 3 15 copyright©amberpasillas2010

2 5 15 1 + 3 15 x 3 = x 5 = Ask yourself what do you multiply the Add and Subtract Fractions Ask yourself what do you multiply the denominator by to get 15. 2 5 15 x 3 = 1 + 3 x 5 = 15 copyright©amberpasillas2010

2 6 5 15 1 + 3 15 x 3 = x 3 = x 5 = Multiply the numerator by the same Add and Subtract Fractions Multiply the numerator by the same number you did in the denominator 2 6 x 3 = 5 15 x 3 = 1 + 3 x 5 = 15 copyright©amberpasillas2010

2 6 5 15 1 5 + 3 15 x 3 = x 3 = x 5 = x 5 = Multiply the numerator Add and Subtract Fractions Multiply the numerator by the same number you did in the denominator. 2 6 x 3 = 5 15 x 3 = 1 5 x 5 = + 3 x 5 = 15 copyright©amberpasillas2010

Add and Subtract Fractions Add your numerators. The denominator stays the same. 2 6 x 3 = 5 15 x 3 = 1 5 x 5 = + 3 x 5 = 15 11 15 copyright©amberpasillas2010

Add and Subtract Fractions 1 2 x 2 = 6 12 x 2 = 1 3 x 3 = + 4 x 3 = 12 5 12 copyright©amberpasillas2010

ALWAYS SIMPLIFY YOUR ANSWER IF YOUR ANSWER IS AN IMPROPER FRACTION! Add and Subtract Fractions ALWAYS SIMPLIFY YOUR ANSWER IF YOUR ANSWER IS AN IMPROPER FRACTION! 4 12 x 3 = 5 15 x 3 = 2 10 x 5 = + 3 x 5 = 15 22 15 copyright©amberpasillas2010

1 7 15 22 15) 22 15 15 7 Add and Subtract Fractions ALWAYS SIMPLIFY YOUR ANSWER IF YOUR ANSWER IS AN IMPROPER FRACTION! copyright©amberpasillas2010

Add and Subtract Fractions 5 20 x 4 = 6 24 x 4 = 1 3 x 3 = - 8 x 3 = 24 17 24 copyright©amberpasillas2010

Add and Subtract Fractions 2 6 x 3 = 3 9 x 3 = 1 1 x 1 = - 9 x 1 = 9 5 9 copyright©amberpasillas2010

Add and Subtract Fractions 4 2 x 2 = 4 8 x 2 = 2 2 x 1 = + 8 x 1 = 8 6 3 = 8 4 copyright©amberpasillas2010

Add and Subtract Fractions 12 4 x 3 = 15 5 x 3 = 10 2 x 5 = - 15 3 x 5 = 2 15 copyright©amberpasillas2010

REMEMBER: To Always Show Your Work and The Giant One! Add and Subtract Fractions REMEMBER: To Always Show Your Work and The Giant One! Take out your study guide!!! copyright©amberpasillas2010

1 Add Fractions 12 4 15 5 10 2 + 3 15 22 15 #11 x 3 = x 3 = x 5 = Find a common denominator. 15 5 x 3 = 10 2 2) Add the numerators. x 5 = + 3 x 5 = 15 3) Keep the common denominator the same. 22 7 1 15 15 4) Simplify or reduce. Change improper fractions to mixed #s. 15) 22 15 7

- Subtract Fractions 5 x 4 = 20 6 x 4 = 24 1 x 3 = 3 x 3 = 8 24 17 24 #12 5 x 4 = 20 6 x 4 = 24 Always SHOW YOUR WORK! This includes the Giant One. 1 x 3 = 3 - x 3 = 8 24 17 Giant One 24