Comparison Estimator

What is Comparison Estimator?

This activity allows the user to understand the estimation process by comparing two objects. Students can choose to compare the length of two lines, the area of two shapes, or the number of objects on each side.

When the two things you are comparing are viewed at the same scale, it is often easier to identify which is bigger, longer, or greater. If their scales are different, however, you can estimate one, then the other, and compare those amounts.

Estimation skills are crucial in day to day life. Being able to estimate well can help in reading maps, making economical purchases, determining how much tip to leave for a meal, telling a friend an accurate time where you can meet them someplace after finishing your chores, and many other daily tasks. Estimation is a useful tool to get a general idea about a quantity or a size when an exact answer is not necessary.

Related Resources

• Activity Estimator
• Activity Estimator Four
• Activity Estimator Quiz
• Activity Fire Assessment
• Activity More or Less Estimator
• Discussion about Making Estimates
• Worksheet Comparison Estimator Exploration Questions
• Worksheet Comparison Estimator Exploration Questions (doc)

How Do I Use This Activity?

This activity allows the user to practice estimation skills. The user must compare two quantities (which may be the number of objects in each of two sets, the lengths of two curves, or the area of two shapes) by estimating.

Controls and Output

• This activity asks you to make three different types of estimations: counting, length, and area. In the center of the activity there are two pictures. For counting problems, the pictures show two groups of objects. You have to estimate whether the number of objects on the left is greater than or less than the number of objects on the right. For length problems, the pictures show two curves. Again, you have to estimate whether the length of the curve on the left is greater than or less than the length of the curve on the right. For area problems, the pictures show two shapes and the same question applies to the areas of the two shapes.
• When the problem is a length or area problem, you will be given a scale in the upper left-hand part of the picture. The length scale looks like this:

  This tells you that the length of the line on the screen is equal to 2 units. You should use these units to estimate the length of the curve. The area scale looks like this:

  

  This tells you that the area of the square on the screen is equal to 1 square unit. You should use these units to estimate the area of the shape.

• To answer a question, choose from the pull-down menu the phrase that best completes the sentence. You can choose "greater than" or "less than." Once you've selected your answer, click the Check Answer button to see if it is correct.
• If you need help, click the Hint button. This will display a grid over the picture. You can use this grid as an aid to your estimation.
• To go to the next problem, click the Next Problem button:
• There are several settings you can control in this activity. You can set the type of problems you see by picking a problem from the Problem Type pull-down menu. If you choose "Random," the activity will give you random problems that may be counting, length, or area problems. If you choose any of the other three options, you will only get problems of that type.
• You can choose from two levels: level 1 and level 2.
• This activity will automatically record how successful you are at answering the questions. To view the score, press the Show Score button at the bottom of the activity and a pop-up window will appear with the scoreboard. To close this pop-up window press the Close button or click back on the main window.
• To pause the scoring, press the Active button at the bottom of the screen and it will change to a Paused button. To resume scoring, press the Paused button.
• To reset the scoreboard, open the scoreboard using the Show Score button and then press the Reset button.

Because this activity randomly generates questions, a feature called Seed Random has been implemented that allows multiple users using different computers to work on the same problem. See Seed Random Help for instructions on using this feature.

Description

This activity allows the user to compare two quantities (which may be the number of objects in each of two sets, the lengths of two curves, or the area of two shapes) by estimating. This activity would work well in small groups of 2-4 for about 20-25 minutes if you use the exploration questions and 10-15 minutes otherwise.

Place in Mathematics Curriculum

This activity can be used to:

• Introduce students to the uses and limits of estimation
• Reinforce basic concepts in geometry such as simple shapes and area
• Show students the importance of comparing scales on different graphical displays

Be Prepared to

• Encourage the students to estimate rather than measure or count
• Discuss how estimation is not as accurate as measurement
• Explain the difference between close, really close, and almost perfect (almost perfect is the mostaccurate)
• Suggest that the students eventually increase the difficulty level

Related Resources

• Activity Estimator
• Activity Estimator Four
• Activity Estimator Quiz
• Activity Fire Assessment
• Activity More or Less Estimator
• Discussion about Making Estimates
• Lesson on Estimation
• Lesson on Estimation (elementary)
• Worksheet Comparison Estimator Exploration Questions
• Worksheet Comparison Estimator Exploration Questions (doc)