Scaled picture graphs and bar graphs
Draw a scaled picture graph and a scaled bar graph to represent a data set; solve one- and two-step comparison, sum, and difference problems using bar charts, pictograms, and tables
What a learner can do afterwards
- Read and draw scaled picture graphs and bar graphs using a stated key or scale
- Use scaled picture graphs and bar graphs to find how many more or fewer one category has than another
- Use graphs and tables to solve two-step totals and comparisons, including the total for the two largest categories
1 · Read
Earlier, each picture stood for 1 item. A scaled key gives each picture a group of items. With '1 square = 5 pets', two squares mean 5 + 5 = 10 pets, or 2 x 5 = 10. Multiplication adds equal groups: multiply the picture or square count by the key number. To redraw with one picture per item, draw as many pictures as the item count.
A pictogram key says 1 ball = 2 votes. Football has 4 balls: 4 x 2 = 8 votes. Tennis has 2 balls: 2 x 2 = 4 votes. With the same key, more pictures mean more votes. For 'how many more', subtract the smaller count from the larger: 8 - 4 = 4 more votes. These bars show the decoded vote counts.
To total the top two choices, multiply each row's picture count by the key number. With 2 votes per picture, rows of 6, 4 and 3 pictures mean 12, 8 and 6 votes. Pick the two largest vote counts and add: 12 + 8 = 20. When a graph or table already gives vote counts, pick the two largest and add. For all choices, add every count.
Label the categories and what you counted. Choose a key or scale. With 5 pets per square, mark equal steps 0, 5, 10, 15 and so on. Division finds how many groups of 5 fit into 25: count 5, 10, 15, 20, 25. There are 5 groups, so 25 divided by 5 = 5 squares. For pictograms, divide the count by the key to find the picture count.
When rows share a key, you can add their picture counts first, then multiply by the key. With 4 votes per picture, rows of 2 and 3 pictures give (2 + 3) x 4 = 20 votes. To compare two categories together with a third, multiply each picture count by the key, add the two counts, then subtract the third count.
For charts with different keys, multiply each row's picture count by its own key before comparing. Four pictures worth 2 votes each show 8 votes. Three pictures worth 3 each show 9 votes. More pictures do not mean more votes when the keys differ. Subtract the decoded counts: 9 - 8 = 1.
Find the key, multiply squares or pictures by it, then add or subtract to compare, total, or find the difference.
The readings and extra practice questions were written for this dataset. The linked videos are credited to Khan Academy; their publisher terms apply.
2 · Watch
Take it off screen
Where it sits
Where this leads
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18 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.