--- title: "Sorting data into categories" description: "Organise and represent data with up to three categories by counting objects in each category and sorting categories by quantity" canonical: https://lightmysky.com/learn/mathematics/sorting-data-into-categories-mt_ylXdiVRAYv source: https://lightmysky.com/learn/mathematics/sorting-data-into-categories-mt_ylXdiVRAYv.md retrieved: 2026-10-19 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Sorting data into categories Organise and represent data with up to three categories by counting objects in each category and sorting categories by quantity Subject: Mathematics · Area: Data & Statistics · Ages 6 to 8 Page: https://lightmysky.com/learn/mathematics/sorting-data-into-categories-mt_ylXdiVRAYv ## Ready when they can - Sort objects into 2-3 categories, count each group, and use the counts to find a total or a missing group count - Read and create a simple table or list showing category names and counts, and use its recorded counts - Order categories from most to fewest or fewest to most ## Lesson: Sorting into groups and counting them You have sorted objects before. Count each group once per object. Keep its name with its count so someone else knows what the number describes. If you need the exact count, count the objects. To compare groups without exact counts, you can also match objects one to one. *(drawing: The named bars show category counts: red 7, blue 4 and yellow 1.)* **Example.** Mia counts 8 star stickers, 2 heart stickers and 5 circle stickers. She writes each name with its count: Stars = 8, Hearts = 2, Circles = 5. Include every group. A missing name or count leaves the record incomplete. To read a bar display, find the named category and read the number reached by its bar. The Stars bar reaches 8, so it records 8 stars. Read a written list or table by matching the category name to its number. Most means the largest count; fewest means the smallest. Equal counts mean equal amounts. Here, dogs have the fewest with 1. Cats and birds both have 6, so they tie for most. For most to fewest, start with the largest count and work down. For fewest to most, start with the smallest and work up. With A = 8, B = 1, C = 4, most to fewest is A, C, B. Fewest to most is B, C, A. **Example.** To find a total, add the counts of the requested groups. Groups with 2, 3 and 4 objects have 2 + 3 + 4 = 9 altogether. If the question asks for only two groups, add only their counts. Keep the category names with the numbers you choose. **Example.** When every object belongs to exactly one group, the group counts add to the whole. A set has 14 objects. Two groups have 3 and 4: 3 + 4 = 7. Count on from 7 to 14: 8, 9, 10, 11, 12, 13, 14. Those 7 new counts give the remaining group's count. This is subtraction: 14 - 7 = 7. **Recap.** Sort, count each group, write the counts down, then order the groups from most to fewest. ## Practice 18 questions on this page, each with its working shown. ## Needs first - [How Many in Total?](https://lightmysky.com/learn/mathematics/how-many-in-total-mt_dmNvjroCPT) - [Data collection and display vocabulary](https://lightmysky.com/learn/mathematics/data-collection-and-display-vocabulary-mt_u5HkSxZECM) - [Sorting into categories](https://lightmysky.com/learn/mathematics/sorting-into-categories-mt_xppl18avyY) ## Opens up - [Interpreting categorical data](https://lightmysky.com/learn/mathematics/interpreting-categorical-data-mt_1VSfm9yiLn) - [Pictograms and tally charts](https://lightmysky.com/learn/mathematics/pictograms-and-tally-charts-mt_c29FaCTNsx) - [Picture & bar graphs](https://lightmysky.com/learn/mathematics/picture-and-bar-graphs-mt_VhBH8wrFC6)