Idiot\'s Guides Basic Math and Pre-Algebra

Chapter 2: Arithmetic 27

WORLDLY WISDOM

There’s a method of multiplication that never requires you to multiply more than

one digit by one digit and takes care of carrying automatically. It’s called lattice

multiplication. You make a grid of boxes with diagonal lines from upper right to lower

left. Factors are written across the top and down the right side, one digit per box. Each

multiplication of one digit by one digit goes in a box, with the tens digit above the

diagonal and the ones below. Add along the diagonals, and read the product down the

left side and across the bottom.

Are you ready for some multi-digit multiplication? Remember your basic facts, and don’t forget
to add zeros to keep the place value columns aligned.

(5  2  4  1)

(Carry 1)

1

23

11

1

0

1

5

5

3

1

4

2

1

7

CHECK POINT

Complete each multiplication problem.

21. 462 v 53


22. 833 v 172


23. 1,005 v 53
    24. 1,841 v 947
    25. 2,864 v 563