Read and interpret bar graphs with different scales

What you will learn

• Read and interpret bar graphs with different scales

Models used: number sentences, stories, diagrams.

Before you start

• Read picture graphs where one symbol represents several objects

Read the scale, then the bar

Each step up the scale stands for 2 votes.

1. Each step up the scale stands for 2 votes.

2. The mango bar reaches 6. That means 6 votes, not 3 votes.

   3 × 2 = 6

3. Both bars use the same scale. Compare their lengths and read the names beside them.

   The apple bar reaches 4. Compare the tops: mango has 2 more votes.

   6 − 4 = 2

   Mango6

   Apple4

   Difference: 2

Worked example: A new example, together

What is the difference between the greatest and least counts?

1. Find what one step on the axis is worth, then read the top of the bar.

   Labels and scales determine the numerical value represented by each category.

2. Each marked interval represents 2.

   What is the difference between the greatest and least counts?

   6

3. Subtract the smaller requested value from the larger.

4. The answer is 6.

5. Check the result against the question we started with.

   Adding the size of the change to the smaller count gives the larger count.

   We found 6. Labels and scales determine the numerical value represented by each category.

Common mistakes to discuss

• Reading the bar as its count. Read the height against the scale. On a scale of 5, a bar of seven blocks shows 35.

Check your understanding

• Read and interpret bar graphs with different scales
• read a bar graph using its scale
• check the answer against the original quantities and units

Explain your reasoning to an adult, then try a fresh question in the interactive lesson. A result from one attempt is not proof of lasting mastery.