Follow the scale
Read bar counts, intervals, zero and ties on a shared numerical scale.
Explore this lesson →8 practice questions · Optional read aloud · Thinking pad
Let’s understand the idea.
- Read what was recorded, the category names and the scale before interpreting a graph.
- A whole picture represents the number in its key. When shown, half a picture represents half that number of items, not half a real object.
- Bars share a zero baseline and one evenly spaced count scale. Equal heights mean equal counts; zero categories remain labeled.
- Changing a key or switching between pictures and bars preserves every category count. To compare combined groups, combine first, then find the difference.
Something to notice
Observe children collecting their own categorical records and independently choosing titles, labels and useful scales for both graph types. The API evaluates specified-scale constructions, named intermediate counts and final comparisons; preset controls and design choices do not establish independent graph design or oral explanations. These are original fictional data sets with four to six categories, counts 0–40 and keys 2, 4, 5 and 10. Whole/half symbols are exact; no partial real items or automatic rounding are implied. Mapping and practice completion do not establish mastery, retention or transfer.
Try it. Change it. Explain it.
Open the lesson to use its pictures and controls. In How it works, connect the picture to the idea. In Play & discover, change the quantities and notice what stays the same. In Your turn, answer questions and use the explanation to check your reasoning.
You can ask for help, draw on the thinking pad, or listen to the question and answer options. Progress distinguishes independent work from work completed with help.
Let’s try it →Curriculum connection
Grade 3 · 3.MD · US Common Core
This lesson is mapped to these standards. A completed activity is practice evidence, not a claim of mastery. Content is checked against the linked official standards and its mathematical models are tested.