A 4×4 magic square with your chosen sum
Two constructions for a 4×4 magic square with any integer sum: the formula 21a+b and a transformation of the normal square with sum 34.
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Clear, organized learning paths that build strong foundations in mathematics and computer science.
Algebra
Fast mental calculation: recognize the structure before calculating
Eighteen explained techniques and their identities, 25 problems and an interactive practice laboratory.
ReadSix Kordemsky puzzles: with and without algebra
Six classic puzzles approached first through insight and then checked mathematically: coins, apples, averages, a current and two meetings.
ReadNotable sums: from Gauss to even and odd numbers
A chain of formulas born from one idea: pair the extremes, then transform the sum of natural numbers into sums of evens and odds.
ReadTen very challenging linear and quadratic word problems
Five reworked classics and five newly framed problems, with equations, constraints, rejected roots and step-by-step checks.
ReadThe same problem, different mathematics: from intuition to parameters
Eight situations explored in primary, lower-secondary, and upper-secondary terms: an advanced model helps the teacher design concrete explanations without imposing it on the child.
Read50 challenging linear word problems with solutions
Fifty challenging real-world problems solvable with first-degree equations. Solutions are hidden and, when useful, include a method without an equation.
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