Tables and
Averages
Learn how to read a table, pick the right numbers, and find the average using \( \text{Average} = \dfrac{\text{Sum}}{\text{Count}} \).
What is a Table?
A table organizes information into rows and columns. Each column has a heading that tells you what kind of number it holds. To answer a question, you find the right row and the right column.
| Student | Test Score |
|---|---|
| Ana | 88 |
| Ben | 92 |
| Cara | 80 |
What is an Average?
The average (also called the mean) is one number that stands in for a whole group. You find it by adding up all the values and dividing by how many there are.
If three friends are 10, 12, and 11 years old, the average age is \( \dfrac{10+12+11}{3} = \dfrac{33}{3} = 11 \) years.
Why Tables + Averages Go Together
Many test questions give you a table and ask for an average. The trick is two steps: first find the right column of numbers, then average just those numbers.
The Core Rule
| Day | Books Read |
|---|---|
| Mon | 3 |
| Tue | 5 |
| Wed | 4 |
Which Column Can Be Averaged?
You can only average columns that hold numbers describing an amount. Columns of names, words, or labels cannot be averaged.
| Pet | Weight (lb) |
|---|---|
| Cat | 9 |
| Dog | 21 |
| Bird | 3 |
Total vs. Average
Be careful! A question may ask for the total (just the sum) or the average (sum divided by count). They are different numbers.
How to Solve These Questions
Worked Example 1
The table shows how many apples each child picked. What is the average number of apples per child?
| Child | Apples |
|---|---|
| Mia | 6 |
| Jon | 8 |
| Lee | 10 |
Worked Example 2
A store recorded its sales. What is the average number of toys sold per day across the 4 days?
| Day | Toys Sold |
|---|---|
| Mon | 12 |
| Tue | 15 |
| Wed | 9 |
| Thu | 16 |
Worked Example 3
This table has two number columns. The question asks for the average height, so pick the height column.
| Plant | Age (wk) | Height (cm) |
|---|---|---|
| A | 2 | 14 |
| B | 3 | 20 |
| C | 4 | 23 |
Common Mistakes
Quick Summary
| Total | Average | |
|---|---|---|
| What it means | The whole amount | One typical value |
| How to find it | Add the values | Add, then divide |
| Formula | \( \text{Sum} \) | \( \dfrac{\text{Sum}}{\text{Count}} \) |
| Question words | "in all", "altogether" | "average", "mean" |
Question 1 of 5
A table lists 4 students and their quiz scores: 7, 9, 8, 8. What is the average score?
Question 2 of 5
A table has columns "Name", "Favorite Color", and "Height (in)". Which column can be averaged?
Question 3 of 5
A store sold these books over 3 days: 10, 14, 12. What is the average number of books sold per day?
Question 4 of 5
A table shows points scored: 4, 6, 5, 7, 8. What is the average points scored?
Question 5 of 5
A table has "Day", "Temperature (\(^{\circ}\text{F}\))", and "Rainy?". You want the average temperature: 70, 72, 68, 74. What is the average?
You've Got This!
Lesson Complete
You can now read a table, choose the right column, and find the average with confidence.