Add or subtract fractions with unlike denominators.

Convert to an improper fraction. Convert to a mixed number. Write in simplest form. Write a fraction that is equivalent to .

VOCAB Least Common Multiple (LCM): Example: Find LCM(6,9) The smallest multiple that is common to 2 or more #’s. Multiples happen when U count by a # Example: Find LCM(6,9) Count by 6: 6 12 18 24 30 36 … Count by 9: 9 18 27 36 … Next Slide >>

Find the Least Common Multiple (LCM) of 4 and 5 Count by 5: 5 10 15 20 25 30 35 … Count by 4: 4 8 12 16 20 24 28 … 20 is the LCM of 4 and 5

Find the Least Common Multiple (LCM) of 4 and 5 Count by 5: 5 10 15 20 25 30 35 … Does 4 go into 5 evenly? No. Does 4 go into 10 evenly? Does 4 go into 15 evenly? No Does 4 go into 20 evenly? YES!! Bingo!!! 20 is the LCM of 4 and 5

EZ Example Find the value of . The fractions already have common denominators. Add numerators. Write in simplest form.

Add or subtract the numerators. Get the bottoms the same by making equivalent fractions (multiply top AND bottom by the same #) (using the least common denominator is optional). Add or subtract the numerators. Write the sum or difference over the common denominator. Write the fraction in simplest form.

Find the value of . The LCM of 3 and 4 is 12. Rewrite fractions. Subtract.

x 5 4 x 2 3 x 1 8 3 = = 3 x 4 12 12

Always Check For Simplest Form or Lowest Terms.

Write each answer in simplest form.

What do you find to be the most difficult part about adding or subtracting fractions?