My Favorite Method for Teaching Percent Word Problems

Word problems involving percent can be especially difficult for students.  Various methods can be used to solve them.  Yet, just as students are gaining confidence at solving percent word problems, they often run across a problem requiring a different approach.  The abundance of situations that can be described, and what specific information is given can make word problems very confusing … not just for kids!

Here is an example of the sort of problem students REALLY struggle with!

A scarf costs $16.48 with tax included. If the tax rate is 5%, what is the selling price of the scarf?

 

After many years of teaching this topic, I’ve decided that the method I will explain here is the most successful of those I’ve tried.  This approach enables students to analyze and solve any word problem involving percents more confidently.

Too often, students identify the base number as the "total".  This leads to many misunderstandings.  The base is "the original amount", which is not always the total.  After this misconception is cleared up, the problem solving immediately becomes easier.  Identifying the base first, even if it is missing, gets students off to a strong start.

Once the issue of identifying the base is clarified, the next step is to determine what to use as the percentage and the rate.  The rate is a "percent" and the percentage is "part of the original amount".  This can be a bit tricky because the part can sometimes be more than the original amount.  For example, suppose you are given a price with tax included.  That price would be more than the original amount, but is the percentage because it is based on the original amount.

In my experience, the most difficult thing for students to understand is that the percentage and the rate must be in agreement.  For example, consider the problem below.

Eight percent of the students in a class of twenty-five are absent today.  How many students are present?

p = ___ number of students present
r = 92% present
b = 25

The base is 25 because that is the original amount of students in the class.  We want to find out how many students are present, and this would be the percentage because it is part of the original amount.  Although 8% can be used as the rate, it represents the percent of students absent.  To find the number of students present quickly, I would use 92% because it is the percent of students present.

This is an overview of this approach.  To become really good at analyzing information and solving a variety of word problems involving percents takes practice.  If you are interested in further support materials, they can be found here.

Get Ready for the Olympics!

I LOVE the Olympics!

That's why I designed this bulletin board, and I'm sharing the Winter Owl Bulletin Board FREE Plans with you.  Use my cute Winter Sport Owls Collection, the free pattern from Classroom Compulsion, or make your own!

The captions included in the plans are editable.  I used ones related to slope and transformations for my bulletin board.

I'm counting down the days until the Olympic Winter Games begin (February 9. 2018) ... will you be ready?

Please leave comments and/or pictures of your creations.  I'd love to see them!

Negative Integer Exponents Stations Activity

So ... I've been teaching exponent rules in my Algebra 1 class.  

Although students learned the negative integer exponent rule in their pre-algebra course, my algebra students never seem to come to me knowing it particularly well.   

I didn't want to spend a lot of time on notes and examples.  Instead, I wanted to see whether or not they could extend the rule to more challenging situations. For this reason, I decided both to review the negative integer exponent rule, and to build on it by using a stations activity.

I designed the stations to demonstrate how the rule remains unchanged, yet the problems increase in difficulty.  My goal for my students was for them to work independently to review the negative exponent rule, then to continue applying it in progressively more challenging problems as they moved through the four stations.

Hint Sheet for Station A

I created a hint sheet with notes and examples to go along with station worksheet A, as well as one to be used with worksheets B-D.  The hint sheets were available to all students.  However, some students needed them, while others did not even pick them up.

All students began at Station A.  

Station A

There, they completed a ten question review worksheet, self-checked their answers with the answer key at that station, and asked me for clarification as needed.

They continued through Stations B, C, and D in the same manner.  You can find the activity here.

I was happy with the way this worked out.  Overall, it took much less time than teaching the lesson in a traditional manner. Students commented that they liked being able to just START since many of them didn't need to be completely retaught. Those who did not remember the rule, grasped it quickly as they worked through the first station and asked questions as needed.  I will definitely use these stations again!