m608ct_secov04B
2/27/07
5:13 PM
Page 1
SECTION
4B
Multiplying Fractions and Mixed Numbers
Lesson 4-4
Why? Some practical problems require students to find a fraction of a number by
using multiplication.
If Jo and Helena each ate 83 of a pizza,
how much of the pizza did they eat altogether?
2
Write 2 as a fraction,
and multiply numerators
and denominators.
83 12 83
2 3
18
6
8
3
4
Simplify the
answer.
Together, Jo and Helena
ate 43 of the pizza.
Dividing Fractions and Mixed Numbers
Lesson 4-5
Why? Real-world measurement problems, such as those relating to sewing and
woodworking, sometimes involve division by fractions or mixed numbers.
Mary has 221 yards of ribbon. How many
lengths of ribbon can she make?
Write the mixed number
as an improper fraction.
1
4
yard
1
1
5
22 4 2
1
2
4
1
Write the division
as multiplication by
the reciprocal.
10
1, or 10
Mary can make 10 lengths of ribbon.
Solving Equations Containing Fractions
Lesson 4-6
Why? Many application problems can be solved using fraction equations.
Cathy uses 3 cans of paint to paint 32 of her room. How many
cans of paint will she use to paint the whole room?
Multiply both sides
of the equation by 32,
the reciprocal of 23.
Cathy will use 421 cans of paint.
3
2
2
r 3
3
2
3 3
r 3
2 1
9
1
r 2, or 42
Write the solution as a
mixed number to represent
cans of paint.