Tag
#number properties
2 essays cross-referencing this thread.
Arithmetic
Factors and Multiples: The Difference, Then a 10-Minute Game
Use one exact test, sort factor and multiple cards, and explain every choice instead of relying on a half-remembered definition.
Patterns
Odd One Out Maths Puzzles: Solve, Test, Explain
Name a rule shared by the group, test every number against it and justify the exception—while allowing another answer when another rule works.