MathXplosion

Lattice Have Fun

Behold, a centuries-old math trick that uses a lattice grid to multiply two-digit numbers. The mystery is simple. This episode introduces the Gelosia method of multiplying large numbers using a cross-hatch, or lattice template. To begin, each digit of the multiplicand is multiplied separately with each digit of the multiplier, and the product is recorded in the corresponding split square. To complete the calculation, you simply add the diagonal columns from top right to bottom left.