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Puzzle of the Day

These puzzles are also printed in Eight days a week, a booklet published by the Association of Teachers of Mathematics.

The three consecutive numbers 5, 6, 7 add up to 18. Can you find three consecutive numbers which add up to 9?, 12?, 30?, 300? Is there a quick way to find them?

Answer: 2, 3, 4; 3, 4, 5; 9, 10, 11; 99, 100, 101. Divide by 3 to find middle.