What is the Chinese multiplication method?

Answer 1

This is also called the Lattice method; it is a very simple method to multiply two numbers together.

1. Draw a grid with the same number of columns as digits in the first number and one more than the same number of rows as digits in the second number.

2. Draw a diagonal line from top right to bottom left in each grid square (extending those at the left hand end down to meet the bottom line of the grid, extended to the left), except the extra bottom row.

3. Write the first number over the gird (one digit to a column) and the second number down the right hand end of the grid, one digit to a row.

4. Now fill in each box in the grid by multiplying the digits of its row and column together, putting the "tens" digit above the diagonal line and the "ones" digit below it. If the result of the multiplication is less than 10, the "tens" digit is a zero (0).

5. Add the digits along each diagonal starting from the right hand end putting the "ones" digit into the extra bottom row of squares under the last digit added in, carrying the "tens" digit of the sum to the next diagonal.

If multiplying decimals together:

1. Write the decimal points next to the grid lines between the digits they fall between.

2. Follow the grid lines from the two decimal points until they meet, then follow the diagonal to the extra bottom row and put the decimal point on the grid line between two digits