**Multiplication Algorithms**

**Lattice Math Algorithm**

**Break Apart Multiplication**

Break down parts of the multiplication problem (easier multiplication, using accurate place value):

22 x 19 =

20 x 10 = 200 (multiply 1 x 2, then add two zeros)

20 x 9 = 180

2 x 9 = 18

2 x 10 = 20

Then add the products:

200

__+180__

380

__+ 18__

398

__+ 20__

418

**Standard algorithm rule**:

13

__x 21__

Multiply the ones column (multiply the one by each number at the top):

13

__x 2____1__

13

Add a zero under the 3 because you are moving to the tens column:

13

__x 21__

13

0

Multiply the 2 by each number at the top:

13

__x ____2____1__

13

__26____0__

Add the products:

13

__ x 21__

13

+ __260__

390

**Use place value and expanded form* to find the product**:

864 x 3 =

800 x 3= 2,400

60 x 3= 180

4 x 3= 12

2,400

__+ 180__

2,580

__+ 12__

2,592

*Review expanded form: 3,492 = 3,000 + 400 + 90 + 2