A Multiplication Algorithm From Roman Times

Lattice

  The lattice algorithm for multiplication has been traced to India, where it was in use before A.D.1100.

Many Everyday Mathematics students find this particular multiplication algorithm to be one of their favorites. It helps them keep track of all the partial products without having to write extra zeros – and it helps them practice their single digit multiplication facts. Based on EM resources

1. Create a grid. Write one factor along the top, one digit per cell.

Write the other factor along the outer right side, one digit per cell.

2. Draw diagonals across the cells.

3.Multiply each digit in the top factor by each digit in the side factor. Record each answer in its own cell, placing the tens digit in the upper half of the cell and the ones digit in the bottom half of the cell.

4. Add along each diagonal and record any regroupings in the next diagonal 0 0 6 8 2 4 3 2 1 2 8 4

0 0 6 8 2 4 3 2 1 2 8 4

1. Create a grid. Write one factor along the top, one digit per cell.

Write the other factor along the outer right side, one digit per cell.

2. Draw diagonals across the cells.

3.Multiply each digit in the top factor by each digit in the side factor. Record each answer in its own cell, placing the tens digit in the upper half of the cell and the ones digit in the bottom half of the cell.

4. Add along each diagonal and record any regroupings in the next diagonal 4 3 5 9 1 5 2 1 1 1 0 4

4 3 5 9 1 5 2 1 1 1 0 4