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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 5s first, 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 total number 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!