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MATH NEWS
Grade 5, Module 3, Topic B
OBJECTIVES OF TOPIC B
Add and subtract fractions with unlike units using
the strategy of creating equivalent fractions.
Add and subtract fractions with sums between 1
and 2.
Solve two-step word problems.
5
th Grade Math
Module 3: Addition and Subtraction of Fractions
Math Parent Letter
This document is created to give parents and students a better
understanding of the math concepts found in Eureka Math (©
2013 Common Core, Inc.) that is also posted as the Engage New
York material which is taught in the classroom. Grade 5 Module 3
of Eureka Math (Engage New York) covers Addition and
Subtraction of Fractions. This newsletter will address making like
units pictorially.
Topic B. Making Like Units Pictorially
Words to know
Unit Fraction Improper Fraction Product Factor
Simplest Form
Equivalent Fraction
Mixed Number
Associative Property
Estimate
Decimal Fraction
Standard Algorithm
Things to Remember:
Unit Fraction – A fraction whereby the numerator (the “top number”) is 1.
Examples:
Improper Fraction- An improper fraction is a fraction where the numerator
(the top number) is greater than or equal to the denominator (the bottom
number.
Examples:
Simplest form (fraction)- A fraction is in simplest form when the
numerator and denominator only have 1 as their common factor.
Example:
1⁄2 is in simplest form because the only common factor for 1 and 2 is 1.
Mixed Number-A mixed number is a whole number and a fraction
combined into one “mixed” number.
Example:
Equivalent Fraction-Fractions which have the same value, even though
they may look different.
Example:
Associative Property - Associative Property states that you can add or
multiply regardless of how the numbers are grouped. By ‘grouped’ we mean
where the parentheses are placed.
Example: 5 x 7 x 2 = (5 x 2) x 7 or 5 x (2 x 7)
Focus Area– Topic B
Module 3: Addition and Subtraction of Fractions
Problem 1:
Step 1: Ask yourself can the fraction one third be added to the
fraction one fourth? No, because the units are not the same.
We need to find like units.
Step 2: Begin the process of finding like units (denominators) by
drawing two rectangular models. Each rectangular model will
represent a different unit fraction shown above.
Step 3: Have both rectangular models show the same size units.
Step 4: Rename each fraction showing like units(denominators).
Now, we can add the units.
)
Divide the
rectangular
model
vertically
into three
equal units.
Shade in one
unit to
represent
one out of
three.
Divide the
rectangular
model
horizontally
into four
equal units.
Shade in one
unit to
represent one
out of four.
Divide the
rectangular
model
showing
into fourths
using three
horizontal
lines.
Divide the
rectangular
model
showing
into thirds
using two
vertical lines.
Each rectangular model now has 12 units.
Application Problem:
Gabe ran
miles on Monday and
miles on Tuesday. How far
did Gabe run on both days. Answer:
(The steps above would be used to determine how far Gabe
ran on both days.)
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For the following problem, draw a picture using rectangular
models.
Solve the following problem using the Associative Property.
The fraction
to
. The only common
factor for 2 and 3 is 1; therefore it is in simplest form.
To find the simplest form we divide both the numerator and
denominator by a common factor.
Marco bought two pizzas for dinner. He ate
of the pizza for dinner and
for breakfast the next morning. Marco took the remaining pizza to school
for lunch. How much total pizza did he eat for breakfast and lunch? How
much pizza did Marco take to school for lunch?
Marco ate a total of one whole pizza
and one-sixth of the second pizza for
dinner and breakfast.
Mixed Number
therefore, you can rewrite the problem using the Associative Property.
Question 2: How much pizza did Marco take for lunch?
Strategy 1: 1 whole pizza
Strategy 2: 1 whole pizza –
pizza eaten =
Marco took five-sixths of a pizza to school for lunch.
Example 1:
Example 2:
Example 3:
= 1 whole pizza