**Lattice Method of Multiplication**

**Lattice Method of Multiplication**

Lattice multiplication, a variations of today's

standard long multiplication were introduced into

Europe by Fibonacci (whose correct name is

Leonardo of Pisa). It requires the preparation of a

lattice (a grid drawn on paper) which guides the

calculation and separates all the multiplications from

the additions.

During the multiplication phase, the lattice is filled in

with two-digit products of the corresponding digits

labeling each row and column: the tens digit goes in the

top-left corner.

During the addition phase, the lattice is summed on the

diagonals.

Finally, if a carry phase is necessary, the answer as

shown along the left and bottom sides of the lattice is

converted to normal form by carrying ten's digits as in

long addition or multiplication.