Blog

Online math resources

Reviews

Curriculum guide

Maria's Math news - a monthly FREE newsletter filled with math teaching information.

May 2012

Subscribe below:

Latest from my blog
This is where you'll find the latest happenings, news, & ideas in math teaching

Math teaching videos
My videos at YouTube show you how to teach concepts.

—much more effective than random drill!

Worksheets
Various worksheets on TONS of math topics you can generate for free!

Curriculum
Advice, reviews, and resources to help you choose a math curriculum!

Online math games, tutorials, and activities
Games you can play online, interactive tutorials, fun math websites and more. Arranged by topic/level for ease of use.

Articles
Learn how to TEACH concepts or about general concerns in math education.

Reviews
In-depth reviews of math products

Math help & tutoring
A list of free message boards, math help websites, and online tutoring services.

My Amazon Store
See some math products I recommend.

Fun and games
I have two games on my site, plus links to many.

(easy hangman)
(difficult)

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

Multiplying in columns - standard way
Free lesson plan from HomeschoolMath.net

Often multiplication in columns is done like shown below. It is still based on the exact same principle (distributive property) you studied in the previous lesson: you simply multiply ones and tens separately, and add. But this time the adding is done immediately after you multiply the tens.

1
63
× 4

2

1
63
× 4

252

Multiply the ones first.

4 × 3 = 12

Place 2 under the line at the ones place, but the tens digit (1) is written above the tens column as a little memory note. This is called carrying to tens.

Then multiply the tens, and add the 1 ten that was carried over.

4 × 6 + 1 = 25

Total of 25 tens, which actually signifies 250. Write the 25 in front of the ones digit (2).

63
× 4

12
+ 240

252

Compare to the method you learned in the last lesson.

In the calculation 4 × 6 + 1 = 25, the 6 and the 1 are actually tens. So in reality we calculate 4 × 60 + 10 = 250.

Look at other examples:

2
27
× 4

8

2
27
× 4

108

4 × 7 = 28

4 × 2 + 2 = 10

6
69
× 7

3

6
69
× 7

483

7 × 9 = 63

7 × 6 + 6 = 48

Compare the method from the last lesson with the one in this lesson:

75
× 8

40
+ 560

600
OR

4
75
× 8

0

4
75
× 8

600

5 × 8 = 40,
4 is carried. 7 × 8 + 4 =
56 + 4 = 60

You can choose which one you use. Discuss with your teacher.

Example problems

1. Multiply. Be careful with the carrying.

53
× 8

51
× 6

62
× 2

46
× 7

18
× 5

39
× 9

46
× 2

17
× 9

35
× 9

With a 3-digit number you might have to carry twice, to tens and to hundreds.

3
238
× 4

2

1 3
238
× 4

52

1 3
238
× 4

952

Multiply the ones first.
4 × 7 = 32

Place 2 under the line
and carry the tens digit (3)
to the tens' column.

Then multiply the tens
digit, and add the 3 tens
that were carried over.
4 × 3 + 3 = 15

Place the 5 in tens place and
carry the 1 into hundreds' column.

Then multiply the hundreds
digit, and add the 1 hundred
that was carried over.
4 × 2 + 1 = 9

Place the 9 in hundreds place.

Look at other examples. Compare to the method of the previous lesson.

2
127
× 4

8

1 2
127
× 4

08

1 2
127
× 4

508

4 × 7 = 28

4 × 2 + 2 = 10

4 × 1 + 1 = 5

127
× 4

28
80
+ 400

508

2. Multiply.

123 × 8	151 × 6	462 × 2
106 × 7	178 × 5	109 × 9
287 × 3	367 × 2	334 × 2

157 × 5	466 × 2	104 × 6

3. Word problems. Write a mathematical sentence for each one.

a) The school has 304 students. To go to the museum, they hired buses which can each seat 43 passengers. How many buses did they need?

b) The school also has 24 teachers. How many seats were left empty when all the students and all the teachers joined the trip?

f) Diaper service provided 90 diapers a week Was that enough for Anna and if not, how many more diapers did she need weekly?

Fill in missing numbers in these multiplications:

		1
×			4

	4	6	8

	1		4
×

	8	7	0

	3		9
×			3

		5

Next lesson: Estimation

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.

Multiplying in columns - standard way Free lesson plan from HomeschoolMath.net

Example problems

Multiplying in columns - standard way
Free lesson plan from HomeschoolMath.net