Adding and Subtracting Fractions Chapter X, Lesson Y.Z Mr. Borowski January 29, 2012
At the end of this lesson we will be able to answer the following questions: • How do we add or subtract fractions? • How do we add or subtract different fractions with different denominators? • Why are we multiplying the fractions by other fractions?
1. How do we add or subtract fractions? • The denominator of the fractions MUST be the same. • Add/subtract the numerators and keep the denominator
2. How do we add or subtract different fractions with different denominators? • Convert the fractions in the equation to have the lowest common multiple (LCM)
3. Why are we multiplying the fractions by other fractions? • Multiplying by a fraction equal to 1 does NOT change the equation, however, it makes it easier for us to solve • *HINT*: The easiest way to convert is to multiply by the denominator of the other fraction
Question 1: In a recent exam in a class of 24, one-eighth of the students got an A, two-thirds got a B, and the rest got a C. What fraction of the class received a C?
Solution: 5 students received a C.
Question 2: Coach Andrews believes his football team has more chemistry when the players decide who should be the captains. So he takes an anonymous vote at the beginning of every year. Out of 66 players, Jamal received 22 votes and Kyle got 20 votes. By what small percentage did Jamal beat out Kyle to become the new captain? *Remember to get percent you need to divide the numerator by the denominator and multiply by 100*
Solution: Jamal won by 3% but since the margin of victory was so close Coach Andrews made Kyle a co-captain.