Russian multiplication

Here is how the russians used to multiply.

74 x 45

First write the calculation with the largest number first

Half the first number ignore any remainder

37

Double the second number

90

Repeat this process

18 180

9 360

4 720

Stop when the left hand number reaches 1

2 1440

1 2880

74 x 45 The next step is to cross out any even numbers in the left hand column

37

Then cross out opposite numbers in the right hand column

90

18 180

9 360

4 720

2 1440

Russian multiplication

1 2880

74 x 45Add the remaining numbers in the right hand column

37 90

18 180

9 360

4 720

2 1440

Russian multiplication

1 2880

90360

2880+

03

2

3

1

3

Finished 74 x 45 = 3 330

57 x 38Now try one for yourself, try to keep ahead of the example

28 76

14 152

7 304

3 608

Russian multiplication

1 1216

304608

1216+

661

1

2

Finished 57 x 38 = 2 166

2

38

Russian multiplication

Try these calculations, check your answers with a friend to correct any mistakes

1) 75 x 19 =

2) 79 x 36 =

3) 51 x 29 =

4) 92 x 57 =

5) 47 x 74 =

1425

2904

7479

5244

3478

Russian multiplication

Try these calculations, check your answers with a friend to correct any mistakes

1) 75 x 19 =

2) 79 x 36 =

3) 51 x 29 =

4) 92 x 57 =

5) 47 x 74 =

1425

2904

7479

5244

3478