math trick

Lattice MultiplicationStep-by-Step

356 * 25 =I don’t

remember how to multiply!!!

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

do Lattice Multiplication.

356 * 25

3 5 62

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 * 25

3 5 62

5

12

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

356 * 25

3 5 62

5

1201

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

356 * 25

3 5 62

5

1201

60

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

356 * 25

3 5 62

5

1201

60

03

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

356 * 25

3 5 62

5

1201

60

03

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

52

356 * 25

3 5 62

5

1201

60

03

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

5251

356 * 25

3 5 62

5

1201

60

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.

5251

0

356 * 25

3 5 62

5

1201

60

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.

5251

00

+1

356 * 25

3 5 62

5

1201

60

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.

5251

00

+1

9

356 * 25

3 5 62

5

1201

60

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.

5251

00

+1

98

356 * 25

3 5 62

5

1201

60

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.

5251

00

+1

98

356 * 25 =8,900

That is Soooo Cool!!!

Thanks!

Lattice Multiplicationwith Decimals

Step-by-Step

3.42 * 6.9 =Ok! I know how to do

Lattice, but I don’t remember how to

multiply with decimals!!!

3.42 * 6.9

3 4 26

9

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.

3.42 * 6.9

3 4 26

9

Place the decimal point above/beside the line in the grid.

..

3.42 * 6.9

3 4 26

9

12

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

..

3.42 * 6.9

3 4 26

9

1242

Multiply 4 * 6 and place the answer in the grid where the lines meet.

..

3.42 * 6.9

3 4 26

9

1242

81

Multiply 3 * 6 and place the answer in the grid where the lines meet. Use a zero as a place holder.

..

3.42 * 6.9

3 4 26

9

1242

81

81

Multiply 2 * 9 and place the answer in the grid where the lines meet.

..

3.42 * 6.9

3 4 26

9

1242

81

81

Multiply 4 * 9 and place the answer in the grid where the lines meet.

63

..

3.42 * 6.9

3 4 26

9

1242

81

81

Multiply 3 * 9 and place the answer in the grid where the lines meet.

6372

..

3.42 * 6.9

3 4 26

9

1242

81

81

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.

6372

8

..

3.42 * 6.9

3 4 26

9

1242

81

81

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.

6372

89

..

3.42 * 6.9

3 4 26

9

1242

81

81

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.

6372

89

+1

5

..

3.42 * 6.9

3 4 26

9

1242

81

81

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.

6372

89

+1

53

.+1

.

3.42 * 6.9

3 4 26

9

1242

81

81

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.

6372

8953

.+1+1

2 .

3.42 * 6.9

3 4 26

9

1242

81

81

Now you need to place the decimal. Follow the lines until they meet.

6372

8953

.+1+1

2 .

3.42 * 6.9

3 4 26

9

1242

81

81

Now drop on the diagonal to place the decimal.

6372

8953

.+1+1

2 ..

3.42 * 6.9

3 4 26

9

1242

81

81

Your answer is 23.598!!

6372

8953

.+1+1

2 ..

3.42 * 6.9 =23.598

That is Soooo Cool!!!

Thanks!