Sort objects or numbers, using one or more than one attribute...

by classifying a given set of numbers according to the number of digits.

by classifying a given set of numbers as odd or even.

by classifying a given set of numbers as fractions or whole numbers.

by finding the difference between two sets of objects that have been sorted by two attributes, and then explain a possible sorting rule that could be used to sort them.

by showing the sorting of a set of objects, using tools like Venn or Carroll diagrams.

by sorting a given set of objects or numbers in more than one way, and explaining how the sorting rules are different.