Counting and Sorting

Grab a handful of mixed buttons, and you might see red ones, blue ones, big ones, and small ones all jumbled together. If someone asked you 'how many red buttons do you have?' it would be hard to answer right away — unless you first put all the buttons into groups. Sorting things into groups, and then counting each group, is one of the very first steps people use to make sense of information. It's also the first big idea in a subject called statistics!

How to sort objects into groups by a shared feature, like color or shape How to count how many objects are in each group How to use tally marks to keep track while counting How to turn your counts into a simple picture graph

Sorting means putting objects together because they share something in common. You could sort a pile of toy animals by type: all the dogs in one pile, all the cats in another. You could sort a basket of fruit by color: red apples in one group, yellow bananas in another. Once things are sorted, it becomes much easier to see how many of each kind you have.

After sorting, the next step is counting each group one at a time. A handy trick for counting a group is using tally marks: one straight line for each item, and every fifth line crosses the first four, like a little gate. Five tally lines grouped this way makes it much faster to count large groups quickly, five at a time instead of one at a time.

Once you know how many are in each group, you can draw a picture graph to show it at a glance. For each group, draw one picture or square for every item in that group, stacked up in a column. A picture graph lets anyone see instantly which group has the most and which has the fewest, just by looking at which column is tallest.