MULTIPLYING FRACTIONSMS. HENRY10/16/13

YOU ALREADY KNOW HOW TO DO THIS…

• SCA ELECTIONS Nick is running for SCA President. There are 3 fifth grade classrooms, 3 fourth grade classrooms, and 4 third grade classrooms. If he needs 2/3 of these classrooms to vote for him in order to win, what is the minimum number of classes he will need to visit during his campaign?• Go on, solve it! But be aware, you might find that your

answer is a bit tricky .

BUT DO YOU KNOW HOW TO DO THIS…?

• SCA ELECTIONS While tallying the votes for the preliminary SCA elections, Mrs. Futch noticed that ¼ of the votes she tallied yesterday were incorrectly tabulated. Today, she correctly tabulated 2/3 of those votes. What fraction of the total amount of votes did she correctly tabulate today?• Not sure how to calculate the answer? Let’s see what we can

do!

FIRST, THINK ABOUT YOUR VOCABULARY

• What do you think we need to pay attention to when we’re gearing up to multiply fractions?• Numerator?• Quotient?• Denominator?• Factors?

• What do you think we might have to be prepared to do when we get our product?• Reduce our answer to the

simplest form

THEN SOLVE IT

• How? Let’s find out!• http://www.youtube.com/watch?v=MDN_D1pDVSc

NOW, ABOUT THAT PROBLEM…

• Can you solve it now?• SCA ELECTIONS While tallying the votes for the preliminary

SCA elections, Mrs. Futch noticed that ¼ of the votes she tallied yesterday were incorrectly tabulated. Today, she correctly tabulated 2/3 of those votes. What fraction of the total amount of votes did she correctly tabulate today?• What’s your answer? Remember, explain how you got it!

LET’S REVIEW (KEY CONCEPT)

• So what’s the “key” to multiplying two fractions?• WORDS Multiply the numerators and multiply the denominators.• EXAMPLES:

• NUMBERS 2/5 × 1/2 = (2 × 1) / (5 × 1)• ALGEBRA a/b × c/d = (a × c) / (b × d), where b and d are not 0.• REMEMBER: You may need to reduce a fraction to simplest form.

YOUR TURN!

• Table Teachers, please come and get the “Problem Solving Practice” sheet from me.• You may work with your Face Partner on this sheet OR you

may work alone, but I reserve the right to split you up if you become too chatty !

EARLY FINISHER—CHOICE ACTIVITY

• If you complete your problem solving handout, please do the following activity:• Create a song, rap, etc. that you could use to teach someone who had never

done it before how to multiply two fractions.• REMEMBER: Your Problem Solving Practice sheet must be finished before

you can do this activity.• IF YOU NEED ADDITIONAL HELP: Please raise your hand, and I will come to

you.• HAVE FUN!