Estimating quantities

Students will estimate items individually. As a whole group, they will check to determine the closest guess.

A lesson plan for grade K Mathematics

By Aimee Stewart

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Related topics

• Learn more about counting, estimation, mathematics, and number sense.

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Learning outcomes

Students will:

• estimate quantities.
• count using one-to-one correspondence.
• group and count objects by 2’s.
• represent numbers by using tallies.
• recognize closest number to actual count.

Teacher planning

Time required for lesson

30 minutes

Materials/resources

• class estimation record sheet
• objects to be estimated (see ideas in supplemental resources)
• transparent container with lid
• chart paper
• marker
• overhead hundreds board
• overhead counters
• overhead pen

Technology resources

overhead projector

Pre-activities

• Students should be familiar with the term “estimate.” Discuss how estimation is used in the real world.
• Students need to understand how the hundreds board is used. Also, the concept of counting by 2’s and representing numbers by tallies should be explained prior to completing the whole group lesson.

Activities

Prior to the whole group lesson (several days or up to a week), a closed container filled with something (beans, M&Ms, marbles, etc.) along with the class estimation sheet should be placed in an accessible area in the classroom. Individually, students can look at container, estimate, and write their guesses on class estimation sheet.

Whole Group Lesson

1. Write the word “estimate” on overhead projector with an overhead pen. Have students repeat this word. Remind them that when we estimate, we make a guess as to how many items are in the container. Tell students when they estimate, they are making a guess.
2. Call on two students to help with lesson. (Keep a record so that different students will be used each week, and you will know what jobs the students have had.) One student will count the estimated objects. This will be done on the overhead so the items can be seen easily. The second student will be writing tallies on the chart as the first student counts them.
3. After the items are counted, the tally mark person needs to write the actual count on the chart.
4. The student who counted the objects then needs to double check his/her count by putting the items back into the container grouping and counting by 2s. The student who wrote the tallies needs to review the tallies by counting by 5s. The teacher needs to recognize both students in some way, either by verbal communication or applause.
5. Teacher puts hundreds board on overhead. As teacher looks over class estimation record sheet, he or she covers numbers that have been written down, on the overhead hundreds board. This is done with overhead counters. It is recommended that the teacher also circle the actual count on the overhead hundreds board as a reminder to students.
6. Once estimates are shown on hundreds board, remind students that it is not important who made the estimate. The important thing is the numbers and which number is closest to the actual count. Also, remind students that all estimates are good.
7. Call on students to tell which numbers are to be removed from the hundreds board. The teacher will do this by taking off the overhead counters from the overhead hundreds board. These will be numbers that are not close to the actual count.
8. When the closest two or three numbers are left, determine the number that is the closest (call this first place), then do the second and third place numbers.
9. Teacher refers to class estimation record sheet to see which student estimated the closest number. Student is recognized and rewarded as teacher sees fit.
10. Teacher closes the lesson by reviewing with students what it means to estimate and gives ideas of how students can make their guesses in the real world.

Assessment

Teacher observation of student estimates will determine if students are able to estimate reasonable quantities and write numerals correctly. A checklist is kept of who made what estimate in relation to the actual count. This will help the teacher see how close each student estimate is.

One student will be observed counting items on overhead using one-to-one correspondence. A second student will also be observed representing the numbers by writing tallies. The teacher will make reflective notes concerning strengths and weaknesses regarding counting and tallies. This will help in creating small learning groups to review and reteach. Also, the teacher will closely observe the student putting the items back into the container grouping and counting by 2’s.

Close teacher observation during the whole group discussion is needed to note students who are able and not able to recognize closest estimate to actual count.

Supplemental information

Suggested items to be estimated:

• math manipulatives
• food
• candy
• toys

Comments

I have used this lesson for four years, revising it as I go. Originally, students wrote their name and estimates on a piece of scrap paper, and placed into a bowl until the whole group lesson.

Early in the school year, I use small numbers of objects. As the year progresses, the amounts get higher.

On the class estimation sheet that is attached, student names are written inside the circle at the top. Students write their estimates below their names.