1. multiplying by 10 by moving the digits left
Level 6 Module 1
Multiplying & Dividing by 10, 100 & 1000

3. © Professor Pete's Classroom. All rights reserved.
Index
Think Bubble Mathematics: Level 6
Module 1
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4. Think Bubble Math: Level 6 Overview
Module 1:
244825_TBM601_xdiv _10_100_1000_.pptx
Module 2:
240903_TBM602_Integers .pptx
Module 3:
244832_TBM603_xdiv_ by_2_3-digit_nos.pptx
Module 4:
241750_TBM604_Fractions _convert_compare.pptx
Module 5:
242003_TBM605_Percent .pptx
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5. Think Bubble Math Worksheets:
Many lessons are supported by corresponding worksheets
Purchasers:
Included in zip file for download
Members:
Access via profpete.com in TBM section
Some lessons recommend that students use hands-on materials
243504_TBM102_WS_Counting_on_back_1_2_3
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6. Navigating in Think Bubble Math on a Computer
Return to Index
Go to other slide:
Right-click screen, click “See All Slides”
Navigate forward & back: click right & left arrows
Start presentation:
Double-click file name or icon
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7. Using Think Bubble Math on a Tablet or Phone
Download free PowerPoint app in iTunes or Google Play:
iPhone or iPad:
Android:
Save Think Bubble file to your device
You may find it helps to install Microsoft OneDrive, to save and find files
If you see a warning about “unsupported content”, you can safely ignore it
We include special fonts to improve the presentation’s appearance
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8. Navigating in Think Bubble Math on a Tablet or Phone
Start presentation:
click “play” button in top bar
Navigate to other slide:
rotate device to portrait, click slide thumbnail at bottom of screen
Navigate forward & back: swipe left & right
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9. (c) Professor Pete's Classroom, 2017. All rights reserved.
Multiply and Divide by 10, 100, 1000
ACMNA130
Multiply and divide decimals by powers of 10
ACMNA123
Select and apply efficient mental and written strategies and appropriate digital technologies to solve problems involving all four operations with whole numbers
(c) Professor Pete's Classroom, All rights reserved.

10. Assumed Prior Knowledge
Students should already be able to:
Recall all basic multiplication and division facts
Explain place value from millions to thousandths
Relate decimal fractions to both base ten concepts and to equivalent common fractions
Associate base ten materials with the relevant numbers and their symbols (numerals)
(c) Professor Pete's Classroom, All rights reserved.

11. A Controversial Position
DON’T:
Tell students to “move the decimal point” when multiplying or dividing by 10, 100, 1000, etc.
27.35 x 1000 = ____________________
DO:
Encourage students to think of the meaning behind the process, and to use place value to ascertain the answer
Since the number is increasing, move digits left 3 places:
Experience and an understanding of base ten numbers leads us to adopt an uncommon approach to this topic
Teachers all over the world teach students to “move the decimal point”
Students all over the world find this confusing, and fail when trying to apply this brute force procedure without understanding
27 35
27 35
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12. Multiplying and Dividing by 10, 100 and 1000
The number slide is a powerful tool enabling students to see what happens to numbers as they are multiplied or divided by a power of 10
The digits remain in the same order, as they move to a different place
Decimal points don’t move; nor should we say add a zero
3.5 x 10
3 5
See our Number Slide Gadget for an online interactive tool that illustrates this idea for multiplying or dividing numbers by 10, 100 or 1000
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13. Accompanying worksheet for Printing
Lesson 1, 2, 3 and 4
Duplicate one per 2 students
Students can create their own number slide
244826_TBM601_Number_slide
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14. Supporting Resources:
Resources at profpete.com
Gadgets Interactive Software
Number Slide (accompanying master)
Number Slide Gadget Use
Number Slide x
Number Slide ÷
Doubling, Halving 2 Digit Numbers Mentally [PowerPoint TBM501]
Number Slide Gadget
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15. (c) Professor Pete's Classroom, 2017. All rights reserved.
Lesson 1: x10 x100
ACMNA130
Multiply and divide decimals by powers of 10
ACMNA123
Select and apply efficient mental and written strategies and appropriate digital technologies to solve problems involving all four operations with whole numbers
(c) Professor Pete's Classroom, All rights reserved.

16. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10
When x 10, the digits move to the left one place =
3 x 10 30 3
Multiplying by 10 is best illustrated by all the digits moving to the left one place
Have students think about whether the answer will be larger or smaller. If larger then the digits move left so the digits have a higher value
Discuss with students changes such as there being no decimal places now, or a zero/s appearing in the Ones place to hold the place
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17. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10
When we multiply a number by 10, the digits move to the left one place =
23 x 10
230
2 3
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18. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10
When x 10, the digits move to the left one place =
3.5 x 10 35
3 5
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19. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10
When x 10, the digits move to the left one places =
400.7 x 10
4007
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20. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10
When x 10, the digits move to the left one place =
21, x 10
210,590.8
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21. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10
When x 10, the digits move to the left one place =
x 10
2091.7
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22. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10
When x 10, the digits move to the left one place =
8900 x 10
89,000
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23. © Professor Pete's Classroom. All rights reserved.
Multiplying by 100
When x 100, the digits move to the left two places
2 x 100 =
200 2
Multiplying by 1o0 is best illustrated by all the digits moving to the left two places
Have students think about whether the answer will be larger or smaller. If larger then the digits move left so the digit have a higher value
Discuss with students changes such as there being no decimal places now, or a zero/s appearing in the Ones place to hold the place
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24. © Professor Pete's Classroom. All rights reserved.
Multiplying by 100
When x 100, the digits move to the left two places =
2.1 x 100
210
2 1
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25. © Professor Pete's Classroom. All rights reserved.
Multiplying by 100
When x 100, the digits move to the left two places =
x 100
413,508
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26. © Professor Pete's Classroom. All rights reserved.
Multiplying by 100
When x 100, the digits move to the left two places =
1, x 100
100,402.5
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27. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10, 100 and 1000 = a)
50.6 x 100
5060 = b)
3000 x 10
30,000 = c)
x 10
93,939 = d)
x 100
4004.1
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28. (c) Professor Pete's Classroom, 2017. All rights reserved.
Lesson 2: x 1000
ACMNA130
Multiply and divide decimals by powers of 10
ACMNA123
Select and apply efficient mental and written strategies and appropriate digital technologies to solve problems involving all four operations with whole numbers
(c) Professor Pete's Classroom, All rights reserved.

29. © Professor Pete's Classroom. All rights reserved.
Multiplying by 1000
x 1000
When x 1000, the digits move to the left three places
2 x 1000 =
2000 2
Multiplying by 1000 is best illustrated by all the digits moving to the left three places
Have students think about whether the answer will be larger or smaller. If larger then the digits move left so the digit have a higher value
Discuss with students changes such as there being no decimal places now, or a zero/s appearing in the Ones place to hold the place
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30. © Professor Pete's Classroom. All rights reserved.
Multiplying by 1000
When x 1000, the digits move to the left three places =
2040 x 1000
2,040,000
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31. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10
When x 10, the digits move to the left one place =
x 10
56,100.3
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32. © Professor Pete's Classroom. All rights reserved.
Multiplying by 100
When x 100, the digits move to the left two places =
x 100
103,010
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33. © Professor Pete's Classroom. All rights reserved.
Multiplying by 1000
When x 1000, the digits move to the left three places =
x 1000
8,180,900
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34. © Professor Pete's Classroom. All rights reserved.
Multiplying by 1000
When x 1000, the digits move to the left three places =
x 1000
2,200,020
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35. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10
When x 10, the digits move to the left one place =
6900 x 10
69,000
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36. © Professor Pete's Classroom. All rights reserved.
Multiplying by 100
When x 100, the digits move to the left two places =
x 100
29,909
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37. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10, 100 and 1000 = a)
x 100
784,460 = b)
x 1000
36,905 = c)
32.09 x 10
320.9 = d)
x 1000
567,030
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38. (c) Professor Pete's Classroom, 2017. All rights reserved.
Lesson 3: ÷ ÷ 100
ACMNA130
Multiply and divide decimals by powers of 10
ACMNA123
Select and apply efficient mental and written strategies and appropriate digital technologies to solve problems involving all four operations with whole numbers
(c) Professor Pete's Classroom, All rights reserved.

39. © Professor Pete's Classroom. All rights reserved.
Dividing by 10
÷ 10
When ÷ 10, the digits move to the right one place =
48 ÷ 10
4.8
4 8
Dividing by 10 is best illustrated by all the digits moving to the right one place
Have students think about whether the answer will be larger or smaller. If larger then the digits move left so the digit have a higher value
Discuss with students changes such as there being no decimal places now, or a zero/s appearing in the Ones place to hold the place
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40. © Professor Pete's Classroom. All rights reserved.
Dividing by 10
When ÷ 10, the digits move to the right one place =
630 ÷ 10 63
6 3
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41. © Professor Pete's Classroom. All rights reserved.
Dividing by 10
When ÷ 10, the digits move to the right one place =
51.8 ÷ 10
5.18
5 1 8
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42. © Professor Pete's Classroom. All rights reserved.
Dividing by 10
When ÷ 10, the digits move to the right one place =
÷ 10
290.16
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43. © Professor Pete's Classroom. All rights reserved.
Dividing by 100
When ÷ 100, the digits move to the right two places =
230 ÷ 100
2.3
2 3
Dividing by 100 is best illustrated by all the digits moving to the right two places
Have students think about whether the answer will be larger or smaller. If larger then the digits move left so the digit have a higher value
Discuss with students changes such as there being no decimal places now, or a zero/s appearing in the Ones place to hold the place
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44. © Professor Pete's Classroom. All rights reserved.
Dividing by 100
When ÷ 100, the digits move to the right two places =
3010 ÷ 100
30.1
3 0 1
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45. © Professor Pete's Classroom. All rights reserved.
Dividing by 100
When ÷ 100, the digits move to the right two places =
150,051 ÷ 100
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46. © Professor Pete's Classroom. All rights reserved.
Dividing by 100
When ÷ 100, the digits move to the right two places =
1,000,000 ÷ 100
10,000
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47. © Professor Pete's Classroom. All rights reserved.
Dividing by 10 and 100 = a)
89,550 ÷ 100
895.5 = b)
9,522,380 ÷ 100
95,223.8 = c)
36,800 ÷ 10
3680 = d)
56.4 ÷ 100
0.564
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48. (c) Professor Pete's Classroom, 2017. All rights reserved.
Lesson 4: ÷ 1000 and revision
ACMNA130
Multiply and divide decimals by powers of 10
ACMNA123
Select and apply efficient mental and written strategies and appropriate digital technologies to solve problems involving all four operations with whole numbers
(c) Professor Pete's Classroom, All rights reserved.

49. © Professor Pete's Classroom. All rights reserved.
Dividing by 1000
When ÷ 1000, the digits move to the right three places =
2000 ÷ 1000 2
÷ 1000 2
Multiplying by 1000 is best illustrated by all the digits moving to the left three places
Have students think about whether the answer will be larger or smaller. If larger then the digits move left so the digit have a higher value
Discuss with students changes such as there being no decimal places now, or a zero/s appearing in the Ones place to hold the place
© Professor Pete's Classroom. All rights reserved.

50. © Professor Pete's Classroom. All rights reserved.
Dividing by 1000
When ÷ 1000, the digits move to the right three places =
1,000,000 ÷ 1000
1000
Dividing by 1000 is best illustrated by all the digits moving to the right three places
Have students think about whether the answer will be larger or smaller. If larger then the digits move left so the digit have a higher value
Discuss with students changes such as there being no decimal places now, or a zero/s appearing in the Ones place to hold the place
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51. © Professor Pete's Classroom. All rights reserved.
Dividing by 1000
When ÷ 1000, the digits move to the right three places =
4010 ÷ 1000
4.01
4 0 1
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52. © Professor Pete's Classroom. All rights reserved.
Dividing by 1000
When ÷ 1000, the digits move to the right three places =
249 ÷ 1000
0.249
2 4 9
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53. © Professor Pete's Classroom. All rights reserved.
Dividing by 1000
When ÷ 1000, the digits move to the right three places =
64,200 ÷ 1000
64.2
6 4 2
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54. © Professor Pete's Classroom. All rights reserved.
Dividing by 1000
When ÷ 1000, the digits move to the right three places =
320,000 ÷ 1000
320
3 2 0
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55. © Professor Pete's Classroom. All rights reserved.
Dividing by 10
When ÷ 10, the digits move to the right one place =
÷ 10
550.05
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56. © Professor Pete's Classroom. All rights reserved.
Multiplying by 10
When x 10, the digits move to the left one place =
7110 x 10
71,100
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57. © Professor Pete's Classroom. All rights reserved.
Dividing by 100
When ÷ 100, the digits move to the right two places =
11,090 ÷ 100
1109
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58. © Professor Pete's Classroom. All rights reserved.
Multiplying by 1000
When x 1000, the digits move to the left three places =
x 1000
403,030
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59. © Professor Pete's Classroom. All rights reserved.
Multiplying by 100
When x 100, the digits move to the left two places =
90.09 x 100
9009
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60. Multiplying and Dividing Large Numbers= a)
3,800,330 ÷ 100
38,003.3 = b)
x 1000
420,060 = c)
599,300 ÷ 10
59,930 = d)
4,700,260 ÷ 1000
4,700.26
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61. Multiplying and Dividing Large Numbers= e)
97.5 x 100
9750 = f)
x 1000
8,400,900 = g)
7603 ÷ 100
76.03 = h)
66,200 ÷ 10
6620
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