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Rates, Ratios and Proportions with Fractions

📖STANDARDS

CCSS.MATH.CONTENT.7.RP.A.1 Compute unit rates, including those that involve complex fractions, with like or different units.

CCSS.MATH.CONTENT.7.RP.A.2.C. Represent proportional relationships by equations

⏰Time Required

30-45 minutes

📲Technology Required

Projector and computer required to watch video in class. Alternatively, students can be assigned to watch on computer, phone or tablet at home. Google apps or PowerPoint required for slide presentation.

📃Lesson Summary

Students watch a 4-minute video giving examples of finding unit rates by simplifying fractions. They solve a problem together as a class and are given a short lecture on solving rate problems with complex fractions. Problems provided can be worked by students individually or done together in class.

📚Lesson Plan

This lesson plan assumes that your students understand simplifying complex fractions. They should know how to divide a fraction by an integer or by another fraction.

1. Watch video explaining unit rates

2. Solve a problem as a class

Using this Google slides presentation, students solve a problem together as a class. They are reminded the meaning of “reciprocal” and that in dividing one fraction by another, you multiply by the reciprocal of the fraction in the denominator. Additional slides give students instruction and tips on solving rates problems that include complex fractions.

3. Solve a variety of problems involving rates and complex fractions

The problem set is found here and the answer key with problems solved step–by-step is here. You know your class best. If you have already covered complex fractions and rate problems, these can be used as formative assessment or review. Alternatively, you may wish to either:

  • Assign the problems, have the students give these a try and then correct together as a class.
  • Select some of the problems to review together and assign the remainder as homework.
  • Assign the problems for students to complete individually, as either in-class work or homework and grade using the answer key provided.

4. Watch a video of a student applying ratio and proportion

At this point, many students will still need further clarification. In this video, Eva shows how she uses ratio and proportion to reduce a recipe for 4 dozen cookies to one for 2 dozen cookies.

Assessment

Students will be assessed based on performance on the problems provided.

State Standards

Missouri Learning Standard 7.RP.A.1

Minnesota Math Standard 7.2.2.1 – Represent proportional relationships with tables, verbal descriptions, symbols, equations and graphs; translate from one representation to another. Determine the unit rate (constant of proportionality or slope) given any of these representations.

Probability and fruit

📖Standards

CCSS.Math.Content.7.SP.C.5
Understand that the probability of a chance event is a number between 0 and 1 that expresses the likelihood of the event occurring. Larger numbers indicate greater likelihood. A probability near 0 indicates an unlikely event, a probability around 1/2 indicates an event that is neither unlikely nor likely, and a probability near 1 indicates a likely event.

CCSS.Math.Content.7.SP.C.6
Approximate the probability of a chance event by collecting data on the chance process that produces it and observing its long-run relative frequency, and predict the approximate relative frequency given the probability.

Time

30-45 minutes, depending on whether the final individual activity is performed in class or outside of class.

📲Technology Required

A projector or smart board is required to show the Google slides presentation in class. It can also be shown using any web meeting software for remote learning. The random fruit basket generator can be used by students in anything with a browser, including computers, tablets or phones. This activity is optional.

📃Summary

The Google slides presentation begins with definitions of probability, impossibility and certainty. Students are then given an example of a basket with different types of fruits and the probability of each. Students each come to the front of the class and pull a piece of fruit from the basket, writing down the probability of their selecting the type they obtained. The class data is used to create a table and compare the obtained probabilities to actual distribution of fruit in the basket. The lesson closes with students creating their own probability question.

NOTE: This lesson plan requires a basket of fruit. You could use pictures of fruit printed out or drawn on paper instead but using actual fruit from your area might be more fun. If you’d rather, though, we do have a random fruit basket generator to use with this lesson.

📚Lesson Plan

1. Presentation on Probability

The Google slides presentation begins with definitions of probability, impossibility and certainty. Students are then given an example of a basket with different types of fruits and the probability of each. Students each come to the front of the class and pull a piece of fruit from the basket, writing down the probability of their selecting the type they obtained. The class data is used to create a table and compare the obtained probabilities to actual distribution of fruit in the basket. The lesson closes with

Students are then given an example of a basket with different types of fruits and the probability of each.

2. Individual students compute probability

Students each come to the front of the class and pull a piece of fruit from the basket, writing down the probability of their selecting the type they obtained. The class data is used to create a table and compare the obtained probabilities to actual distribution of fruit in the basket. If students are learning at home, we have a random fruit basket generator to use with this lesson. After setting THE SAME NUMBER OF EACH FRUIT for everyone to enter, have each student click on the basket to select a random fruit and see the probability.

3. Group Activity

Complete table included in presentation as a class. Compare obtained probabilities with expected. Discuss that the expected probabilities are for a large number of trials and that it is usual to have the observe probabilities not match up exactly – or even closely – with the actual proportions when the sample size is small.

4. Probing questions

These questions are included in the presentation. Ask the class what the probability is of selecting a kiwi fruit, remembering that there are not any kiwi in the basket. If Annie’s family owns an apple orchard and her basket contains only apples, what is the probability of selecting an apple? If students need a reminder, return to the definitions of probability, impossibility and certainty at the beginning of the lesson.

5. Individual Activity

Students will create their own probability activity using household items. This activity can be performed at home, having family members draw items, or can be performed in the classroom using items in the classroom, such as different colors of pencils, or even pieces of paper with different words or pictures.

Assessment

Individual formative assessment is conducted throughout this activity by having students write the probability of the specific fruit they selected and by their performance on the individual activity creating their own probability sample and recording the results. Students can also write their answers to the in-class questions on probabilities of 0 and 1, then comparing these to the correct answer.

State Standard

Missouri Learning Standards (MLS)●7.DSP.C.5a Understand that the probability of a chance event is a number between 0 and 1 that expresses the likelihood of the event occurring. Larger numbers indicate greater likelihood. A probability near 0 indicates an unlikely event, a probability around 1/2 indicates an event that is neither unlikely nor likely, and a probability near 1 indicates a likely event.

Minnesota Math Standard 6.4.1.2 – Determine the probability of an event using the ratio between the size of the event and the size of the sample space; represent probabilities as percents, fractions and decimals between 0 and 1 inclusive. Understand that probabilities measure likelihood.

Minnesota Math Standard 6.4.1.4 – Calculate experimental probabilities from experiments; represent them as percents, fractions and decimals between 0 and 1 inclusive. Use experimental probabilities to make predictions when actual probabilities are unknown.

Reading & comparing bar graphs

📖Standards

CCSS.MATH.CONTENT.6.SP.B.5 Statistics & Probability: Summarize numerical data sets in relation to their context.

CCSS.MATH.CONTENT.7.RP.A.2.B Ratios & Proportional Relationships: Identify the constant of proportionality (unit rate) in  tables, graphs, equations, diagrams, and verbal descriptions of proportional relationships.

⏰Lesson Time

40- 50 minutes

📲Technology Required

Device with web-browser – Chromebook, laptop or desktop computer, iPhone or iPad

📃Summary

This lesson introduces students to reading and comparing bar graphs with proportional relationships. Students receive a slide or handout with four bar graphs and complete a set of cards with questions or complete the activity in Google slides . The lesson ends with an adventure game that includes discussion of interpreting bar graphs.

📚Lesson Plan

Related lesson plan

If you have not watched the videos on Mayan Trading and Distributions, you may want to check out this lesson plan first.

Preparing for the lesson – Options

Print out the cards if students do not have home Internet access or if you want to use the cards to do the activity in class. (Note: Business card stock may not be the best $10 I have spent as a teacher, but it’s high on the list. I  don’t know what it is about cards that makes something seem like a game but I have had the greatest success with activities like this one.). Here is a PDF for the cards. If you would like to download the cards to edit and add your own questions, here is a Microsoft Word doc.

If students are learning from home, you can copy the Google slides presentation to your Google classroom and assign to students.

1. Individual Activity

Use this Google slides presentation to introduce and explain the assignment.

Print out the “Graphs” page or display it using a Smartboard, projector or in your Google classroom. Each student / group is required to complete the cards using the graphs provided.

Example of card with graph question
One of a pair of cards comparing graphs

2. Class Activity

After the students have completed the assignment, which should take around 10-15 minutes, have students share their findings to these questions with the class. Discuss and review the different questions and answers that can come from the same set of data.

3. Play Games!

Students can play the AzTech: The Story Begins to practice statistics in a history adventure game. Link available from the games page, select the device on which you want students to play. Available free for Chromebook, Android or iOS.

AzTech: The story Begins
Play AzTech: The story begin

Assessment

AzTech Games Teacher Reports – Teachers can access standards-aligned student reports including answers to problems, number of correct answers, quiz results and pre-test/post-test results.

Students’ responses in the activities above, both individually and as a group, provide formative assessment of their ability at interpreting and extrapolating from graphical data.

State Standards

Minnesota Math Standard 7.2.2.1 – Represent proportional relationships with tables, verbal descriptions, symbols, equations and graphs; translate from one representation to another. Determine the unit rate (constant of proportionality or slope) given any of these representations.

Distributions and Mayan Trading

📖Standard

7.SP.A.1 Understand that statistics can be used to gain information about a population by examining a sample of the population; generalizations about a population from a sample are valid only if the sample is representative of that population. Understand that random sampling tends to produce representative samples and support valid inferences.

Minnesota State Standard – History Sub-strand 4, Standard 15 “North America was populated by indigenous nations that had developed a wide range of social structures, political systems, and economic activities, and whose expansive trade networks extended across the continent.”

Time

20- 30 Minutes 

📲Technology Required

Device with web-browser – Chromebook, laptop or desktop computer, phone or tablet

📃Summary

The two videos here combine math and social studies, because, clearly, the Maya understood math. The concept of distributions is introduced in the context of trading, explaining why some objects are more valuable. Students play AzTech: Meet the Maya, which teaches measures of central tendency. The lesson concludes with a question and another video on distributions.

📚Lesson Plan

1. Watch video – Mayan Trading (1:57)

The Mayan trading video is based on an idea from one of my favorite history teachers, who says that history is more than just names and dates but also how people lived, what they used, what they did. It also has a bar chart of the relative value of objects. It explains that the Maya traded less common items for more common ones and that items that were more difficult to obtain were more valuable.

2. Play AzTech: Meet the Maya

Next, have students start the AzTech games series. They can play AzTech: Meet the Maya online or using an iPad. We recommend downloading the game onto your iPhone or iPad for better performance.

3. Question to test understanding

José tried to trade a banana for a quetzal feather and a villager threw a spear at him. Why would the villager do that? Explain using math. Extra points if you can discuss distributions in your explanation.

4. Video giving the answer to the word problem on distributions (5:15)

This five-minute video introduces distributions and variability and gives an example of computing a weighted mean from a frequency distribution.

OPTIONAL You can also copy this Google slides presentation to your own classroom if you’d rather modify the explanation for your own lecture. The slides can also be printed out and sent home with students who do not have Internet access.

ASSESSMENT

You can view your students’ progress on mastering these standards by viewing your teacher reports. The link to the teacher dashboard for AzTech: Meet the Maya student reports can be found on this page. You should have received a password during the Growing Math training.

State Standards

Minnesota State Standard 6.4.1.1 – Determine the sample space (set of possible outcomes) for a given experiment and determine which members of the sample space are related to certain events. Sample space may be determined by the use of tree diagrams, tables or pictorial representations.

Related Lesson

Distributions and Mayan Trading (Bilingual English & Spanish) – This lesson is a bilingual version of the lesson above and features resources in English and Spanish.

Time Rate Distance Problems

📖 Standards

CCSS.Math.Content.7.EE.B.3
Solve multi-step real-life and mathematical problems posed with positive and negative rational numbers in any form (whole numbers, fractions, and decimals), using tools strategically. Apply properties of operations to calculate with numbers in any form; convert between forms as appropriate; and assess the reasonableness of answers using mental computation and estimation strategies.

CCSS.Math.Content.4.NBT.B.5 Multiply a whole number of up to four digits by a one-digit whole number, and multiply two two-digit numbers, using strategies based on place value and the properties of operations. (Common Core Standards)

📃 Summary

Time-rate-distance problems are word problems that involve the distance an object will travel at a certain average rate for a given period of time. Because we have found many students struggle with this type of problem, we find it so helpful to have multiple examples through videos, slides, and through a video game. In all of these problems, students solve for distance. Video, game and presentation resources are available in both English and Spanish.

The formula for distance problems is: 

distance = rate × time or d = r × t

📲 Technology required

The game AzTech: The Story Begins can be played for free on iOS (iPad and iPhone) and in a web browser on any computer. The game can be installed in an iPad and played off-line by students who do not have reliable Internet access.

Time required

15-25 minutes – time varies depending upon discussion of questions and length of game play allowed.

📚 Lesson Plan

Watch video introducing students to Time-Rate-Distance problems

Introducing time-rate-distance problems 3:04

This brief video uses number bonds as one means of finding the total number of hours, then multiplies hours by rate to find the total distance. We work step by step through an example to find how far Spanish troops needed to ride to attack the Aztecs.

2. Video or Presentation of time-rate-distance example

How many miles did Grandma drive? 1:24

Teaching Options

Students can watch another video solving for distance. If it takes 2 1/2 days to get to Honduras from Iowa, and Grandma drives 60 miles per hour without stopping, what is the distance from Iowa to Honduras? This video solves the problem step by step, beginning with converting 2.5 days to hours.

Alternatively, teachers can use this presentation as PowerPoint or in Google slides to present the same material either in class or in a web meeting. These presentations are also available in Spanish as PowerPoint and in Spanish as Google slides.

3. Video or Presentation of a second time-rate-distance example

How far is Iowa from Texas? 1:19

Teaching Options

Students can watch another video solving for distance. If it takes Grandpa one day to get from Iowa to Texas and he drives 55 miles per hour, what is the distance from Iowa to Texas? This video shows, step by step, how to solve this problem.

Alternatively, teachers can use this presentation as PowerPoint or in Google slides to present the same material either in class or in a web meeting. These presentations are also available in Spanish as PowerPoint and in Spanish as Google slides.

Assessment

Bonus question in level 1 of AzTech: The Story Begins

Play AzTech: The Story Begins. Not only will students have fun and be exposed to educational content on Latin American history, but they will also have to answer mathematics questions to progress. Instruct students to be sure to answer the first bonus question, shown above. Remind them that the icon at the bottom of the screen can be used to pull up a calculator. (There is no arrow on the screen in the game. It is merely shown above for emphasis.) Once students have played the game, you can look in the AzTech teacher reports to see an individual students response. You will need to know your students’ usernames. To see an example of a report, enter the username “ddtester” .

State Standards

Minnesota Math Standard 6.2.3.2 – Solve equations involving positive rational numbers using number sense, properties of arithmetic and the idea of maintaining equality on both sides of the equation. Interpret a solution in the original context and assess the reasonableness of results.

Minnesota Math Standard 7.1.2.1 – Add, subtract, multiply and divide positive and negative rational numbers that are integers, fractions and terminating decimals; use efficient and generalizable procedures, including standard algorithms; raise positive rational numbers to whole-number exponents.

Minnesota Math Standard 4.1.1.3 – Multiply multi-digit numbers, using efficient and generalizable procedures, based on knowledge of place value, including standard algorithms.