Multiplying Whole Numbers

Lesson 2-2

Example: 563 x 37

56337x

1

2

4

4

39098

1

16+13

1

8

1

0

1

2

Example: 53 x 26182618 has more digits (4) than 53 (3), so it goes on top.

2618 53x

4

2

58

1

700

4

90

3

13+

457

1

831

Lattice MultiplicationStep-by-Step

356 x 25 =I don’t

remember how to multiply!!!

HELP!!! I can help!! Let me show you how to

do Lattice Multiplication.

356 x 25

3 5 6

2

5

Make a grid the exact size of your problem. A 2 digit number times a 3 digit number gets a 2 x 3 grid. Draw a diagonal line in each box.

356 x 25

3 5 6

2

5

12

Multiply 6 * 2 and place the answer in the grid where the lines meet.

356 x 25

3 5 6

2

5

120

1

Multiply 5 * 2 and place the answer in the grid where the lines meet.

356 x 25

3 5 6

2

5

120

16

0

Multiply 3 * 2 and place the answer in the grid where the lines meet. Use a zero as a place holder.

356 x 25

3 5 6

2

5

120

16

0

03

Multiply 6 * 5 and place the answer in the grid where the lines meet.

356 x 25

3 5 6

2

5

120

16

0

03

Multiply 5 * 5 and place the answer in the grid where the lines meet.

52

356 x 25

3 5 6

2

5

120

16

0

03

Multiply 3 * 5 and place the answer in the grid where the lines meet.

52

51

356 x 25

3 5 6

2

5

120

16

0

03

Now add the diagonals and place the answer below the grid. Be sure to carry to the next diagonal if you have a 2 digit answer.

52

51

0

356 x 25

3 5 6

2

5

120

16

0

03

Now add the diagonals and place the answer below the grid. Be sure to carry to the next diagonal if you have a 2 digit answer.

52

51

00

+1

356 x 25

3 5 6

2

5

120

16

0

03

Now add the diagonals and place the answer below the grid. Be sure to carry to the next diagonal if you have a 2 digit answer.

52

51

00

+1

9

356 x 25

3 5 6

2

5

120

16

0

03

Now add the diagonals and place the answer below the grid. Be sure to carry to the next diagonal if you have a 2 digit answer.

52

51

00

+1

98

356 x 25

3 5 6

2

5

120

16

0

03

Now add the diagonals and place the answer below the grid. Be sure to carry to the next diagonal if you have a 2 digit answer.

52

51

00

+1

98

356 x 25 =8,900

Which method do you prefer?