Download Russian Peasant Multiplication

Math Lesson Plan
Activity: Teach students a math concept
Grade: 5
Concept: Russian Peasant Multiplication
Materials
Chalk and chalkboard
Objectives
Students will:
1. Learn the Russian Peasant Multiplication method.
2. Be able to perform this method on their own.
3. Identify why it is easier than regular multiplication
Procedures
1. Tell students you are going to teach them a new, easier method of doing
multiplication. Say it only requires them to know their two times tables and how to
double and divide numbers by two. Ask if they think they can do that, and whether or
not you can prove it.
2. Introduce the Russian Peasant Multiplication method. Tell the class to pick two
numbers to multiply together. (But not too big, say with no more than two digits in
each #, so the teacher can teach it easily).
3. Write the numbers on the board, side by side. Tell the class it’s usually best to put the
smaller number first. Tell students they will always halve the first number and double
the second number.
4. When halving the first number, tell students if the number being divided is odd, they
will throw the remainder of one when they divide away. For example if they pick 35,
the answer would be 17.5, they would just use 17, and continue on normally as though
nothing had happened. They will continue halving until the number is one.
5. Then once all the numbers have been doubled or halved as instructed, ask which are
odd numbers in the first column. Once they have identified these numbers tell them
they will add the numbers in the second column that corresponds with the odd
in the first column.
Example:
numbers
35
x
42
17
84
8
168
4
336
2
672
1
1344
( numbers in blue are the numbers that correspond with the odd numbers in green
from the 1st column . The blue numbers in 2nd column you add together)
So:
42 + 84 + 1344 = 1470
and:
35 x 42 = 1470
6. Ask the class which is easier, multiplying out 35 and 42 or just using the Russian
Peasant method.
7. Do more examples on the board, and ask if there are any questions. Ask students to
come up and do the method themselves, and explain what they are doing as they are
doing it.
Closure
Assign problems for homework or an in class assignment. For example:
1. 22 x 41
2. 17 x 32
3. 21 x 67
4. 40 x 80
5. 9 x 19
6. 14 x 99
7. 75 x 101
8. 130 x 132
9. 115 x 120
10. 15 x 200
Assessment
1. Students can perform multiplication by the usual method and by Russian Peasant
multiplication.
2. Can recognize why this might be easier than regular multiplication
3. Using this method is a another example of multiplying by breaking down the steps to
use smaller numbers, thus making it easier for students who aren’t as advanced as some of
the other students.
4. Students will complete the assigned problems successfully and understand the concept.