Estimating Fraction Sums in Word Problems, Day 1

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SWBAT solve word problems with estimation.

Big Idea

Students work on estimation word problems.

Do Now

10 minutes

The Do Now problem is a review and continuation of the topic of estimating fraction sums.  My goals for this problem are students should know how to estimate fractions, find the sum, explain whether it's an overestimate or underestimate, and why.


Estimate the sum. Round each number to the nearest whole number, then add.  Explain if it's an overestimate or underestimate.


 After 5 minutes, I will instruct students to share their answers with their group. (MP3)  This will allow them to check their answers and hear different explanations.  Also, I will encourage students to comment on others' explanations, whether it's offering a suggestion or agreeing with their explanation.



Mini Lesson

10 minutes

This is the first day of a 2 day lesson.  I will handout the  BL Estimating Sums Group Problems worksheet to students.  We will work as a class through example 1 and I will model what estimating for a word problem looks like.

Ex. 1 - Janice is making a model of a house that she designed.  She wants to put wood molding around two rooms in the model.  She measures and finds that she needs 3 ¼ feet of molding for one room and 2 3/8 feet of molding for the other room.  She has 5 ½ feet of molding.

1.  Estimate whether she has enough molding. 

2.  Describe your strategy for estimating the answer.

3.  Is your estimate an overestimate or an underestimate of the sum?

We will go through each step together, with students creating a KWL chart (similar to GCF and LCM Word Problems KWL Chart)  in their notebooks.  What do you know or what information is given to you?  What do you want to know?  How are we going to find the estimate? What did you learn?  Does your estimate make sense?

Group Work

20 minutes

After modeling example 1 for students, they will work in their groups to complete the rest of the worksheet (Copy of BL Estimating Sums Group Problems).  Groups will be instructed to work collaboratively, making sure each member has an opportunity to be heard.

Students are grouped heterogeneously based on a previous exit ticket. Lower level math students may use a number line or I will provide them with fraction strips, if necessary.

I will circulate throughout the groups to observe if and how students are using the benchmarks.

After 10 minutes, I will conclude the group work and inform students that they will continue the work the following day.

Lesson Review

5 minutes

Students will share any observations from their work with word problems.

Do you have a different strategy from your group? Do you disagree with their answers or explanations?