Competition Math Arena

Diophantine Equations

Simon's Factoring Trick

Count positive (x, y) with xy + ax + by = c.

Practise

Difference of squares

Count positive (x, y) with x² − y² = N.

Practise

Linear Diophantine

Count positive (x, y) with ax + by = c.

Practise

Pell's equation

Find the smallest x with x² − Dy² = 1.

Practise

Frobenius number (Chicken McNugget)

The largest amount two coprime coins cannot pay.

Practise