Download topic 8 guided notes

Name _____________________
Topic 8 Guided Notes
Multiplying Fractions & Mixed Numbers
Information, Definitions, Solutions
Key Words/Topic
and Assignments
8.1 Multiplying a fraction
and a whole number
Today’s Concept There are times when we need to multiply a fraction times a
whole number. The easiest way to do this is to turn the
whole number into a fraction and then multiply the two
fractions together. Any whole number can be made into a
fraction by using the number as the numerator and
placing a 1 in the denominator.
2/3 * 15 = 2/3 * 15/1
When you multiply fractions first multiply the numerators
times the numerators.
2*15 =30
Then multiply the denominators times the denominators
(YOU DO NOT NEED OR WANT COMMON
DENOMINATORS!!)
3*1= 3
Place the numerator over the denominator and reduce.
Remember a fraction can be read as a division problem when
reducing.
30/3 or 30 ÷ 3 = 10
Group Work
1-8 on page 186.
Show work when
appropriate.
Use complete sentences
when appropriate.
Don’t forget your labels.
HOMEWORK: 10-25 P.
187 in textbook.
Often times in a “story problem” we can tell that fraction
multiplication is necessary because of the word “OF”. For
example, “Mr. Levine read 3/4 of his 24 comic books. How
many comic books did he read?” If you multiply 3/4 by 24
then you will get the answer.
1.
Group Work
1-8 on page 186.
Show work when
appropriate.
Use complete sentences
when appropriate.
Don’t forget your labels.
2.
3.
HOMEWORK: 10-25 P.
187 in textbook.
4.
5.
6.
7.
8.
Key Words/Topic
and Assignments
8.3 Multiplying Fractions
Information, Definitions, Solutions
Today’s Concept We multiply fractions just like I showed you yesterday.
Refer to your 8.1guided notes.
However, there are ways to make multiplying fractions
easier. Remember when we are done with a fraction
problem, we always have to reduce the answer to simplest
form. Sometimes it is easier to reduce before multiplying.
Let’s look at multiplying 12 * 14
16 24
To simply before multiplying you look to see if the
numerator of the 1st fraction has a common factor with
denominator of the 2nd fraction. Do they? Yes the GCF =
12. You can reduce the numerator of the 1st fraction and
denominator of the 2nd fraction by a factor of 12.
12 * 14
1 * 14
16 24 becomes 16 2
Now look at the numerator of the 2nd fraction and the
denominator of the 1st fraction. They also have a common
factor; this time 7. Reduce the numerator of the 2nd fraction
and the denominator of the 1st fraction by the common factor.
1 * 14
1 *7
16 2 becomes 8 2
Now multiply across to get 7/16-already simplified! It is
often easier to deal with smaller numbers and that is why you
may want to simplify before multiplying.
Group Work
1-6 on page 190.
Show work when
appropriate.
Use complete sentences
when appropriate.
Don’t forget your labels.
HOMEWORK: 8-26 P 191.
In textbook.
1.
2.
Group Work
1-6 on page 190.
Show work when
appropriate.
Use complete sentences
when appropriate.
Don’t forget your labels.
3.
4.
HOMEWORK: 8-26 P 191.
In textbook.
5.
6.
Key Words/Topic
and Assignments
8.4 Multiplying Mixed
Numbers
Information, Definitions, Solutions
Today’s Concept There are two methods for multiplying mixed numbers. One
method uses the distributive property. The other method
converts the mixed numbers into fractions first. We will
concentrate on the conversion method.
In order to convert a mixed number into a fraction follow
this process:
Convert 5 1/4 into a fraction.
1. Multiply the denominator by the whole number.
5*4=20
2. Add the product of your multiplication to the
numerator 20 + 1 = 21.
3. This becomes the new numerator, the denominator
stays the same.
5 1/4 = 21/4
Once you’ve converted the mixed numbers to fractions you
multiply the exact same way as before!
2.
Group Work
2-10 even on page 192.
Show work when
appropriate.
Use complete sentences
when appropriate.
Don’t forget your labels.
HOMEWORK: 11-27 P.
192 in textbook.
4.
Group Work
2-10 even on page 192.
6.
Show work when
appropriate.
Use complete sentences
when appropriate.
Don’t forget your labels.
HOMEWORK: 11-27 P.
192 in textbook.
8.
10.