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Session 4 of 8
Making a
Tally Chart
We have our survey data. Now we organize it using tally marks — the fastest way to count!
Data Science for Young Minds · Grade 2
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Today's Plan
What We're Doing Today
- Hook — which is faster to count?
- What are tally marks and how do we draw them?
- ⭐ Groups of 5 — the crossing mark!
- Build a class tally chart together on the board
- Build your own tally chart from your Session 3 data
- Brain break — finger tally!
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Opening Hook
Which Is Faster to Count?
Your teacher has two sets of marks on the board. Try to count each one!
Random check marks vs. Tally groups of 5
- Which side did you count faster?
- Why was one easier than the other?
- What's special about putting marks in groups?
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Lesson
What Is a Tally Mark?
A tally mark is a vertical line that stands for ONE thing we counted.
Each time someone gives an answer, we draw one tally mark. Simple!
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Lesson
The Magic Fifth Mark!
When we get to 5, we draw the fifth mark crossing through the group — like a fence!
𝄻 = 5
Four lines standing up, one line crossing through them
Groups of 5 let us count quickly — 5, 10, 15, 20… instead of 1, 2, 3, 4, 5, 6, 7, 8…
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Lesson
Counting Tally Groups
When we have tally marks, we count by 5sfirst, then add the extras.
Tip: Count the complete groups first (×5), then count the leftover marks and add them on!
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Lesson
What Is a Tally Chart?
A tally chart is a table with rows for each answer choice, a column for tally marks, and a column for the total.
| Season | Tally Marks | Total |
|---|
| Summer | 𝄻 | | | 7 |
| Fall | | | | | 3 |
| Winter | 𝄻 | 5 |
| Spring | | | | | | 4 |
| TOTAL | | 19 |
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Class Practice
Let's Build One Together!
Your teacher is going to call out the class survey results from Session 3 — one answer at a time.
- Watch the board as each mark is added
- Add the same mark on your own sheet
- When we reach 5 — draw the crossing mark!
- Fill in the totals when all marks are done
Count out loud together as each mark goes up: "One… two… three… four… FIVE — cross it!"
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Your Turn!
Build Your Own Tally Chart
Use YOUR survey results from Session 3. Build a tally chart on your worksheet.
- Look at your recording sheet from Session 3
- Draw the tally chart table with 4 rows + total row
- Add tally marks for each response you recorded
- Count up and fill in the Total column
- Add up all totals for the grand total
You have 10 minutes. Use the tally mark anchor if you forget how to draw the groups!
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Brain Break — Finger Tally!
Your teacher calls out a number.
Hold up your fingers to show that many tally marks!
Use one hand = 1 group of 5.
Try: 3 … 7 … 5 … 12 … 9
Count by 5s, then add the extras!
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Debrief
Reading Our Tally Charts
Now that your chart is built, you can answer questions about your data!
- ⭐ Which season had the most tally marks?
- Which season had the fewest tally marks?
- Did any two seasons have the same number?
- What is the totalnumber of responses?
Your tally chart turns scattered check marks into organized, readable data. Great work!
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Big Idea
Why Organize Data?
Raw data (check marks)
Scattered marks that are hard to read quickly. You have to count every single one.
Tally chart (organized)
Marks in groups of 5 with totals. You can see patterns at a glance!
Organizing data doesn't change what we found — it just makes it easier to understand and share.
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Vocabulary
Words to Know
Tally mark
A vertical line (|) used to count things one at a time
Tally chart
A table using tally marks to organize and count data
Total
The final count — add up all tally marks in a group
Frequency
How many times something appears in the data
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Worksheet Time
Complete Your Worksheet
- Part 1 — Vocabulary in your own words
- Part 2 — Build your tally chart from Session 3 data
- Part 3 — Answer: most, fewest, total
- Part 4 — Tally mark practice (convert numbers)
- Take-home — Tally count something at home!
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Wrap Up
Session 4 Complete!
- Tally marks count things one at a time
- We group them in 5s with a crossing mark
- Tally charts organize data in rows with totals
- Organized data is much easier to read and compare
Coming up — Session 5: We take our tally chart and turn it into a bar graph — a picture of our data!