Make a tally chart for the number of students in the third-, fourth, and fifth-grade classes: 26, 25, 27, 27, 26, 28, 27.

These sites show you how to make tally charts.

http://www.google.com/search?q=tally+chart&rlz=1C1AVSX_enUS414US423&espv=210&es_sm=122&tbm=isch&tbo=u&source=univ&sa=X&ei=X4pcUsWFBMXuyQHgxIHQCQ&ved=0CCkQsAQ&biw=711&bih=453

To create a tally chart for the number of students in the third-, fourth-, and fifth-grade classes, you can use a vertical line to represent each student and group them into sets of five. Here is an example of a tally chart:

Third Grade:
26 students: ||||

Fourth Grade:
25 students: ||||
27 students: |||||

Fifth Grade:
27 students: |||||
26 students: ||||
28 students: ||||||
27 students: |||||

Each vertical line represents one student and the sets of five lines are grouped together.

To create a tally chart for the number of students in the third-, fourth-, and fifth-grade classes, you can follow these steps:

1. Start by drawing a vertical line to represent a tally mark.
2. Make groups of five tally marks, with each group representing five students.
3. Begin by tallying the first number, which is 26. Draw five vertical lines and cross them diagonally to the right for the first group. Then draw one more vertical line to complete the tally for 26: |||/|.
4. Move on to the next number, which is 25. Draw five vertical lines and cross them diagonally to the right for the first group. Then draw one more vertical line to represent the remaining student: |||/.
5. Continue this process for the remaining numbers: 27, 27, 26, 28, 27.
- For each occurrence of 27, draw five vertical lines crossed diagonally to the right for the first group. Then draw two more vertical lines to represent the remaining students: |||/||
- For each occurrence of 26, draw five vertical lines crossed diagonally to the right for the first group. Then draw one more vertical line to represent the remaining student: |||/.
- For 28, draw two groups of five vertical lines crossed diagonally to the right. Then draw three more vertical lines to represent the remaining students: ||||/|||.
6. Once you have tallied all the numbers, count the number of tally marks in each group to determine the total number of students.

Here is the tally chart for the given numbers:

______________________________________________
Grade 3: |||/| |||/| ||||/||| (/ indicates a group of five tally marks)
Grade 4: |||/|| |||/|| |||/||| (/ indicates a group of five tally marks)
Grade 5: |||/|| |||/|| |||/|| ||||/||| (/ indicates a group of five tally marks)
______________________________________________

In the end, you would find that there are a total of 26 students in the third-grade class, 25 students in the fourth-grade class, and 27 students in the fifth-grade class.