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(easy hangman)
(difficult)

The ideas in this lesson are taken from Math Mammoth Multiplication 2 book. Only a few examples of each problem type are shown; you should make more problems of each kind for the student.

This lesson explains the partial products algorithm for multiplying a two- or three-digit number in columns that can be easier for some children to grasp than the usual algorithm.

# The "easy way" to multiply in columns — the partial products algorithmFree lesson plan from HomeschoolMath.net

You can also do 5 × 34  vertically (in columns), using distributive property.

Multiply the ones first. Then multiply the tens and place
the result underneath. Remember,
the 3 in 34 is signifying 30.

 34 ×  5 20
 34 ×  5 20 150
 34 ×  5 20 +  150 170

5 × 4 = 20

5 × 30 = 150

The video below also explains this same idea: first students are taught to multiply two- or three-digit numbers in parts (such as multiplying 3 × 89 as 3 × 80 and 3 × 9, and adding those) as a preparation for learning the usual multiplication algorithm.

Multiply the ones. Multiply the tens. Add.
 64 ×  8 32
 64 ×  8 32 480
 64 ×  8 32 +  480 512

1.  Multiply.

 53 ×  2 61 ×  5 63 ×  5 35 ×  6 17 ×  5 99 ×  5

 47 ×  8 35 ×  8 72 ×  5 77 ×  7 46 ×  6 88 ×  7

2.  Write a mathematical sentence(s) for the problems.  Multiply using the principle above (distributive property).

 a)  All seven houses on the Cat Lane have seven cats living in them.  How many legs do those cats have total? d)  Jane bought seven cards and seven chocolate boxes for her seven friends.  The cards cost total \$14, and the boxes cost total \$35.  How much was her total bill?   How much did one card cost?   One chocolate box?

If you have a 3-digit number, the process is similar:    3 × 184

Multiply the ones first.  Then multiply
the tens.
Then multiply
the hundreds.

 184 ×  3 12
 184 ×  3 12 240
 184 ×  3 12   240 300
 184 ×  3 12 240 +  300 552
3 × 4 = 12 3 × 80 = 240 3 × 100 = 300

Multiply ones: tens: hundreds:

 326 ×  3 18
 326 ×  3 18 60
 326 ×  3 18 60 900
 326 ×  3 18 60 + 900 978

3.  Multiply.

 353 ×  2 161 ×  5 327 ×  3 123 ×  3 103 ×  9 167 ×  5 199 ×  5 420 ×  2 245 ×  4

Can you figure out what was multiplied?

 × 4 2 0 + 1 6 0

 × 7 4 2 + 1 4 0

 × 6 5 4 2 4 0 + 6 0 0

Multiply in columns - the standard algorithm

New! Times Tales is now on DVD!

The fast, FUN, and easy way to learn multiplication. Learn the upper times tales in two sittings using mnemonic stories.