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More Christmas Boxes
What size square should you cut out of each corner of a 10 × 10 grid to make the box that would hold the greatest number of cubes?
Clever Santa
All the girls would like a puzzle each for Christmas and all the boys would like a book each. Solve the riddle to find out how many puzzles and books Santa left.
Colour in the Square
Can you put the 25 coloured tiles into the 5 × 5 square so that no column, no row and no diagonal line have tiles of the same colour in them?
2-Digit Square
A 2-digit number is squared. When this 2-digit number is reversed and squared, the difference between the squares is also a square. What is the 2-digit number?
Binomial
By considering powers of (1+x), show that the sum of the squares of the binomial coefficients from 0 to n is 2nCn
Direct Logic
Can you work through these direct proofs, using our interactive proof sorters?
Two Trees
Can you find the distance between the two trees using the information given?