I begin this lesson by reading the book “Tally O’Mallley” by Stuart Murphy and Cynthia Jabar. I like to use this book because it really brings the concept of tally marks to a real life application. Plus the kids love the humorous illustrations!
I explain that tallying is a quick way to show how many. It is also helpful when recording the results of a survey or sorting several different types of things into groups. Tallies are abstract representations of numbers, and so students are getting the chance to reason abstractly (MP2) by converting numbers into tally marks.
Some students may forget to count the diagonal line in a graph of 5 tally marks. I make sure they understand that tally marks are organized in groups of 5. A group of 5 is made by drawing four vertical lines, and then a fifth line is drawn through the first four. I write tally marks for the numbers 1 to 10 on the board. I then demonstrate how to count by fives and then count on single tally marks.
After demonstrating how to count using tally marks, I ask the students:
If children need additional experiences reading tally marks, you might provide them with the numbers 1 to 20 represented in tallies. Have them write each number.
Explain that in today’s lesson children will read charts that use tallies to show numbers.
I direct students' attention to the first slide on the Read Tally Marks.pptx. (For those struggling students, I give them counters or two different size paperclips to help with a concrete model of the crayons we are sorting on the slide.) Read the following problem aloud:
Jane is sorting her crayons. How can she sort the crayons into two groups?
If children have difficulty representing the longer and shorter crayons with counters, you might suggest that they use large and small paper clips to show the crayons in two sizes.
Discuss a different way to sort the crayons.
I then have a student come up to the board and tell the class how they would sort the crayons, and then have them draw tally marks to show how many of each.
Then looking at the second slide, I direct the discussion:
Before turning them loose for their independent practice, I display the slide that has the same graph as the first problem on their worksheet. We review how to write tally marks again.
As the students begin their independent practice using Read Tally Charts_worksheet.docx, I remind them to count the slashed group of tally marks as five and single marks as one.
For struggling students, review how to count tally marks. Make sure children understand that they can show five with 5 marks, but when we tally, we show five with 4 marks and 1 mark across that group. Have children count aloud from 1 to 5 for the tally marks in a slashed group.
To close out the lesson, I have students use words, numbers, or pictures to show how to group and count tally marks for the number 8 in their math journals.