 The ideas in this multiplication lesson are taken from Multiplication 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 by whole tens - by 10, 20, 30 etc.
|
| 9 × 10 = ___
10 × 10 = ___ 11 × 10 = ___ 12 × 10 = ___ 13 × 10 = ___ |
14 × 10 = ___
15 × 10 = ___ 16 × 10 = ___ 17 × 10 = ___ 18 × 10 = ___ |
19 × 10 = ___ 20 × 10 = ___ 21 × 10 = ___ 22 × 10 = ___ 23 × 10 = ___ |
24 × 10 = ___ 25 × 10 = ___ 26 × 10 = ___ 27 × 10 = ___ 28 × 10 = ___ |
|
What pattern do you see? |
Since multiplication can be done in any order one wishes, or 25 ×
10 = 10 × 25, this rule/pattern works in either case.
1. Multiply.
| 10 × 11 = ___
56 × 10 = ___ 10 × 98 = ___ 12 × 7 = ___ 20 × 10 = ___ |
18 × 10 = ___
10 × 10 = ___ 10 × 0 = ___ 9 × 8 = ___ 77 × 10 = ___ |
10 × 5 = ___
97 × 10 = ___ 10 × 82 = ___ 9 × 9 = ___ 2 × 10 = ___ |
| Note that 20 = 10 × 2. We can use that to multiply by 20.
For example,
20 × 11 = 10 × 2 × 11 Now multiply first 2 × 11 = 22. Then use the easy rule for multiplying by ten: 10 × 2 × 11 = 10 × 22 = 220. So we have 20 × 11 = 220. |
1. Multiply by 20. First break 20 down into 10 ×
2.
|
||||||||
|
||||||||
|
| What is the easy rule for multiplying by 20? |
| Note that 30 = 10 × 3. We can use that to multiply by 30.
For example,
30 × 9 = 10 × 3 × 9 = 10 × 3 × 9 = 10 × 27 = 270 Note that 50 = 10 × 5. We can use that to multiply by 50. For example,50 × 7 = 10 × 5 × 7 = 10 × 5 × 7 = 10 × 35 = 350 Note that 80 = 10 × 8. We can use that to multiply by 80. For example,80 × 6 = 10 × 8 × 6 = 10 × 8 × 6 = 10 × 48 = 480. |
2. Multiply. First break 20, 30, 40, etc down into 10 × a number.
|
|
||||||||||||||||
|
|
Write down here the results from the last exercise:
|
3. Multiply.
| a. | d. |
| 40 × 5 = ____
8 × 20 = ____ 7 × 70 = ____ 30 × 4 = ____ 3 × 40 = ____ 70 × 4 = ____ |
70 × 11 = ____
6 × 40 = ____ 12 × 30 = ____ 8 × 80 = ____ 11 × 40 = ____ 4 × 50 = ____ |
4. For each multiplication, write two division sentences.
|
d. 3 × 30 = | ||||
|
e. 7 × 40 =
|
h. 9 × 60 = |
5. Divide. Think backwards of the multiplication rules you've learned
in this lesson.
| a. 120 × 10 = | c. 100 × 10 = | d. 200 × 10 = |
| i. 120 × 20 = | k. 120 × 60 = | l. 180 × 60 = |
| m. 160 × 40 = | o. 560 × 70 = | p. 420 × 60 = |
6. Continue the patterns.
|
a. 100 × 10 = 200 × 10 = 300 × 10 = 400 × 10 =
|
d. 100 × 50 = 150 × 50 = 200 × 50 = 250 × 50 = |
|
|
|
|
Learn the upper |
 Download my Geometry workbook with lots of hands-on drawing problems! |
HOMESCHOOL MATH NEWSLETTERHomeschool Math Newsletter comes out once monthly, and includes math teaching articles and tips, Math Mammoth news, and all kinds of little "tidbits" such as math news, interesting links, or humor. The content is equally good for all of us who teach math (not just homeschooling parents). When you subscribe, you will alsoreceive a GIFT of over 280 FREE math worksheets and sample pages from Math Mammoth books for grades 1-8. Note: This is a double opt-in list. You will FIRST get an email that asks you to confirm your email address. PLEASE check also your SPAM/JUNK folder for this confirmation email. Take a peek at the previous volumes here!. The newsletter service is by Aweber.com. Your email address will not be shared, sold, or distributed to anyone else. |
| Download 280+ QUALITY math worksheets |
| Link to us Sitemap Contact About Privacy Advertise Homeschool links Educational links |
|
|
 |
|
 |
|
Copyright 2003-2008 Homeschool math http://www.homeschoolmath.net/ |
P.S. ....
| Check out these short video clips from my favorite band - Rockabilly.US. They play oldies, Elvis, country, and top hits of the 50s and 60s. It's a show with large band, costumes, choreography, little skits, "Kid Kritters", 6 dancing/singing girls, junior dancer troupe, etc. | |
|
"Be My Baby" originally by the Ronettes |
Impossible Dream (Elvis song) |
| Most importantly, the band wants to use the uplifting and energetic music to bring some fun, happiness and encouragement into people's lives. They're doing it selflessly to help others, and don't get paid for any of it themselves. And I admire that! | |
