Types of Number Puzzles: Six Kinds and How to Crack Each
Sequences, equations, digit riddles, weighing and counting, rod equations and board sums: the six types of number puzzles, with worked examples.
Riddle10 blog
Articles about counting
Coin Total Puzzles: Largest Unpayable Total and Fewest Tokens
Which totals can two token values pay, what is the largest one they cannot, and how few tokens will do? A ladder method, worked example and practice.
Fence Post Riddle: Why a 15 m Fence Needs 6 Posts
A straight 15 m fence with a post every 3 m needs 6 posts, not 5. Learn the gaps-plus-one rule, when it changes, and where the same trap hides.