Number Pyramid
Number Pyramid is a free addition and subtraction puzzle where each brick equals the sum of the two bricks it sits on. Some bricks are given, and you work out the rest by adding upward or subtracting downward. Every pyramid has exactly one answer you can reach by logic alone, from small 3-row pyramids to 5-row challenges. It is great for practising mental maths and step-by-step reasoning at any age.