How do you use benchmark fractions to
solve story problems with unlike fractions?
James and Mary are making
1
cookies. James has cup of sugar
2
1
and Mary has cup. About how
3
much sugar do they have?
In this lesson you will learn
to estimate fraction sums and
differences by using
benchmark fractions
Let’s
Review
Let’s
Review
We have learned to visualize fractions
using the dollar and the number line.
0
1
4
2
4
3
4
4
4
A Common
Mistake
Let’s
Review
1
1
>
4 2
>
1
1
<
2
4
Core
Lesson
Let’s
Review
3
Tari has
of a bag of puppy
8
food for her new puppy. Her
mom said to add it to the
grocery list when she had about
1
of a bag. Does Tari need to
2
add puppy food to the list?
Fractions close
1
to have
2
numerators that
are about (one
half of) the
denominator.
Core
Lesson
Let’s
Review
Mikki is bringing cookies to Tari’s house for a
sleepover and to meet Tari’s new puppy. Mikki
5
1
has of a bag of chocolate chip cookies and a
4
8
bag of oatmeal cookies. Does Mikki have a full
bag of cookies to bring to Tari’s house?
0
1
0
1
Core
Lesson
Let’s
Review
7
Sarah has of the money she needs for a movie
8
3
ticket. Her brother Lee has 1 of the money he
4
needs for a movie ticket. If they combine their
money, will they have enough for two tickets?
0
1
0
1
0
1
In this lesson you have
learned use benchmark
fractions to solve story
problems with unlike fractions
by using benchmark fractions.
Guided
Practice
Let’s
Review
1
Anthony has sold 1 of a box full of Boy Scout
5
9
of
10
a box full of Girl Scout cookies. Who has sold more
cookies?
cookies for his troop. His sister Anna has sold
0
1
0
1
0
1
Extension
Let’s
Review Activities
1 1
Using the benchmark fractions , , and
4 2
3
, model these on number lines, model two
4
fractions that are equivalent using
additional number lines. Create a story
problem to go with your equivalent
fractions.
Extension
Let’s
Review Activities
Describe three fractions that are:
A. Close
B. Close
C. Close
D. Close
to
to
to
to
one-fourth
one-half
three-fourths
one whole.
For each example, explain your reasoning
using full sentences.
Quick Quiz
Let’s
Review 11
Tari has
13
of the rocks she needs for her
11
fish tank. Is
closer to one-half or one13
whole?
1
Mikki needs
of her room painted light
2
12
pink. She has
completed so far. Is she
24
finished?