Sorting into categories
Classify objects into given categories, count the number in each category, and sort the categories by count
What a learner can do afterwards
- Sort a set of shapes by colour and count how many in each group
- Sort objects by size (big/small) and state how many in each category
- Identify which category has the most/fewest after sorting and counting
1 · Read
Sorting means making groups by a rule. For colour sorting, put red things together and blue things together. For size sorting, make separate big and small groups. Check the rule for each object before choosing its group.
To find a group's count, count only the objects in that group, once each. You can also read a recorded count beside the group's name. Here, Red = 8 and Pink = 2. The words name the groups; the numbers give their counts.
Compare group counts. A bigger number means more objects; a smaller number means fewer. The biggest count is the most, and the smallest is the fewest. Equal counts mean equal amounts. Here, yellow and green tie for most because both have 7.
To find the total across groups, count every object without restarting at 1. These groups have 2, 3 and 4 dots. Count the first group to 2, continue to 5 through the next group, then continue to 9. There are 9 dots altogether.
Check sorting before you trust a group's count. If a big object is in the small group, move it to the big group. Move any small object found in the big group too. Then count each group again. A correct total count does not tell you whether every object is in the right group.
Check counting too. Give every object one number. In a group of five dots, someone touches four once and leaves the fifth untouched. They have skipped a dot. If you only know that a count is too small, you still need to find out what happened.
Sort things into groups, count each group, then see which group has more.
The readings, questions and flashcards were written for this dataset. The linked video is by Khan Academy.
2 · Watch
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Where it sits
Where this leads
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