1. © T Madas

2. 6 5 9 0 1 8 4 . 4 2 3 PLACE VALUES Tenths Thousandths Hundredths
Hundred Thousands
Ten Thousands
Thousands
Millions
Hundreds
Tens
Units
Tenths
PLACE VALUES
Hundredths
Thousandths
© T Madas

3. 9 1 8 4 . 7 2 3 1 9 8 7 2 3 How many hundreds in this number?
How many thousands in this number?
How many tens in this number? 8
How many tenths in this number? 7
How many hundredths in this number? 2
How many thousandths in this number? 3
© T Madas

4. There is another way of looking at this
9000
+100
+80 +4
+7/10
+2/100
+3/1000
+ 0.7
+0.02
+0.003
There is another way of looking at this
… and another way …
© T Madas

5.
9000
+100
+80 +4
+7/10
+2/100
+3/1000
+ 0.7
+0.02
+0.003
Decimals are just a special way of writing fractions
out of 10,
out of 100,
out of 1000 etc
Percentages are just a special way of writing fractions
out of 100.
© T Madas

6. © T Madas

7. To multiply a whole number by:10
We add one zero at the end of the number
100
We add two zeros at the end of the number
1000
We add three zeros at the end of the number
And so on
31 x 10 =
514 x 100 =
670 x 10 =
43 x 1000 =
310
51400
6700
43000
© T Madas

8. Multiplying two whole numbers with zeros at the end
We ignore the zeros at the end of the two numbers
We multiply the non-zero digits of the two numbers
We put at the end of the answer zeros equal to the total zeros we ignored
20 x 30 =
40 x 50 =
300 x 40 =
20 x 120 =
60 x 500 =
600
2000
12000
2400
30000
© T Madas

9. To multiply any number by:10
100
1000
We “move” the decimal point one place, in the direction which makes the number bigger
We “move” the decimal point two places, in the direction which makes the number bigger
We “move” the decimal point three places, in the direction which makes the number bigger
And so on
© T Madas

10. 3.1
31.
3.1 x 10 =
3.1
0.31
5.14
51.4
5.14 x 10 =
5.14
0.514
4.36
436.
4.36 x 100 =
4.36
0.0436
6.317
6317.
6.317 x 1000 =
6.317
© T Madas

11. 41.
410.
41 x 10 =
41.
4.1
x =
And so on…
© T Madas

12. To divide any number by:10
100
1000
We “move” the decimal point one place, in the direction which makes the number smaller
We “move” the decimal point two places, in the direction which makes the number smaller
We “move” the decimal point three places, in the direction which makes the number smaller
And so on
© T Madas

13. 8.6
86.
8.6 ÷ 10 =
8.6
0.86
3.75
37.5
3.75 ÷ 10 =
3.75
0.375
9.63
963.
9.63 ÷ 100 =
9.63
0.0963
4.891
4891.
4.891 x 1000 =
4.891
© T Madas

14. Looking at things differently
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15. 3 1 4 x 10 3 1 4 314 x 10 = 3140 This is what really happens:
THOUSANDS HUNDREDS TENS UNITS TENTHS 3 1 4
x 10
THOUSANDS HUNDREDS TENS UNITS TENTHS 3 1 4
© T Madas

16. 8 3 4 x 100 8 3 4 8.34 x 100 = 834 This is what really happens:
HUNDREDS TENS UNITS TENTHS HUNDREDTHS 8 3 4
x 100
HUNDREDS TENS UNITS TENTHS HUNDREDTHS 8 3 4
© T Madas

17. 7 6 1 x 1000 7 6 1 7.61 x 1000 = 7610 This is what really happens:
THOUSANDS HUNDREDS TENS UNITS TENTHS HUNDREDTHS 7 6 1
x 1000
THOUSANDS HUNDREDS TENS UNITS TENTHS HUNDREDTHS 7 6 1
© T Madas

18. 5 2 ÷ 10 5 2 520 ÷ 10 = 52 This is what really happens:
THOUSANDS HUNDREDS TENS UNITS TENTHS 5 2
÷ 10
THOUSANDS HUNDREDS TENS UNITS TENTHS 5 2
© T Madas

19. 6 5 ÷ 100 6 5 65 ÷ 100 = 0.65 This is what really happens:
HUNDREDS TENS UNITS TENTHS HUNDREDTHS 6 5
÷ 100
HUNDREDS TENS UNITS TENTHS HUNDREDTHS 6 5
© T Madas

20. Multiplying & Dividing by numbers with zeros at the end
Practice on
Multiplying & Dividing
by numbers with zeros
at the end
© T Madas

21. Multiply and Divide by numbers with zeros at the end
43 x 10 =
430
16 x 20 =
320
30 x 40 =
1200
50 x 20 =
1000
12 x 20 =
240
21 x 40 =
840
50 x 30 =
1500
32 x 30 =
960
630 ÷ 10 = 63
420 ÷ 20 = 21
2200 ÷ 10 =
220
450 ÷ 30 = 15
32000 ÷ 100 =
320
320 ÷ 80 = 4
4100 ÷ 100 = 41
4800 ÷ 80 = 60
© T Madas

22. Multiply and Divide by numbers with zeros at the end
32 x 20 =
640
150 x 20 =
3000
40 x 40 =
1600
50 x 600 =
30000
12 x 30 =
360
220 x 40 =
8800
60 x 30 =
1800
25 x 300 =
7500
280 ÷ 20 = 14
390 ÷ 30 = 13
3200 ÷ 20 =
160
4200 ÷ 70 = 60
5400 ÷ 60 = 90
32000 ÷ 800 = 40
3600 ÷ 90 = 40
4800 ÷ 800 = 6
© T Madas

23. Multiplying & Dividing by numbers with zeros at the end
Practice on
Multiplying & Dividing
by numbers with zeros
at the end
© T Madas

24. Multiply and Divide by numbers with zeros at the end
43 x 10 =
430
16 x 20 =
320
30 x 40 =
1200
50 x 20 =
1000
12 x 20 =
240
21 x 40 =
840
50 x 30 =
1500
32 x 30 =
960
630 ÷ 10 = 63
420 ÷ 20 = 21
2200 ÷ 10 =
220
450 ÷ 30 = 15
32000 ÷ 100 =
320
320 ÷ 80 = 4
4100 ÷ 100 = 41
4800 ÷ 80 = 60
© T Madas

25. Multiply and Divide by numbers with zeros at the end
32 x 20 =
640
150 x 20 =
3000
40 x 40 =
1600
50 x 600 =
30000
12 x 30 =
360
220 x 40 =
8800
60 x 30 =
1800
25 x 300 =
7500
280 ÷ 20 = 14
390 ÷ 30 = 13
3200 ÷ 20 =
160
4200 ÷ 70 = 60
5400 ÷ 60 = 90
32000 ÷ 800 = 40
3600 ÷ 90 = 40
4800 ÷ 800 = 6
© T Madas

26. Multiplying & Dividing by 10, 100, 1000 …
Practice on
Multiplying & Dividing
by 10, 100, 1000 …
© T Madas

27. Multiply and Divide by 10, 100, 1000, etc
43 x 10 =
430
8.6 x 10 = 86
17 x 100 =
1700
4.7 x 100 =
470
123 x 10 =
1230
1.25 x 10 =
12.5
58 x 1000 =
58000
2.813 x 1000 =
2813
570 ÷ 10 = 57
42 ÷ 10 =
4.2
8600 ÷ 10 =
860
465 ÷ 100 =
4.65
32000 ÷ 100 =
320
320 ÷ 100 =
3.2
4100 ÷ 100 = 41
4109 ÷ 100 =
41.09
© T Madas

28. Multiply and Divide by 10, 100, 1000, etc
66 x 10 =
660
2.6 x 10 = 26
31 x 100 =
3100
8.7 x 100 =
870
149 x 10 =
1490
1.75 x 10 =
17.5
10 x 1000 =
10000
4.394 x 1000 =
4394
360 ÷ 10 = 36
213 ÷ 10 =
21.3
7500 ÷ 10 =
750
465 ÷ 100 =
4.65
45000 ÷ 100 =
450
870 ÷ 100 =
8.7
3400 ÷ 100 = 34
8005 ÷ 100 =
80.05
© T Madas

29. Multiply and Divide by 10, 100, 1000, etc
131 x 10 =
1310
9.63 x 10 =
96.3
30 x 40 =
1200
5.52 x 100 =
552
20 x 50 =
1000
4.05 x 10 =
40.5
70 x 500 =
35000
9.506 x 1000 =
9506
930 ÷ 10 = 93
7.002 x 100 =
700.2
1800 ÷ 10 =
180
35 ÷ 10 =
3.5
2.7 x 10 = 27
809 ÷ 100 =
8.09
4.1 x 10 = 41
1876 ÷ 1000 =
1.876
© T Madas

30. Multiply and Divide by 10, 100, 1000, etc
16 x 10 =
160
8.65 x 10 =
86.5
123 x 10 =
1230
2.71 x 100 =
271
48 x 100 =
4800
2.25 x 10 =
22.5
5.8 x 10 = 58
4.916 x 1000 =
4916
570 ÷ 10 = 57
52 ÷ 100 =
0.52
8600 ÷ 10 =
860
375 ÷ 100 =
3.75
32 ÷ 10 =
3.2
665 ÷ 100 =
6.65
41 ÷ 10 =
4.1
792 ÷ 1000 =
0.792
© T Madas

31. Multiply and Divide by 10, 100, 1000, etc
151 x 10 =
1510
7.62 x 10 =
76.2
364 x 100 =
36400
1.92 x 100 =
192
9.2 x 10 = 92
4.85 x 10 =
48.5
7.83 x 10 =
78.3
6.906 x 1000 =
6906
930 ÷ 10 = 93
72 ÷ 1000 =
0.072
1800 ÷ 10 =
180
305 ÷ 100 =
3.05
17 ÷ 10 =
1.7
609 ÷ 1000 =
0.609
413 ÷ 10 =
41.3
1656 ÷ 1000 =
1.656
© T Madas

32. Multiply and Divide by 10, 100, 1000, etc
16.1 x 10 =
161
7.62 x 10 =
76.2
3.64 x 10 =
36.4
1.48 x 100 =
148
9.2 x 100 =
920
4.11 x 10 =
41.1
0.83 x 10 =
8.3
0.096 x 1000 = 96
930 ÷ 100 =
9.3
27 ÷ 1000 =
0.027
1825 ÷ 10 =
182.5
305 ÷ 1000 =
0.305
1.7 ÷ 10 =
0.17
609 ÷ 100 =
6.09
413 ÷ 10 =
41.3
696 ÷ =
0.0696
© T Madas

33. Quick Test on
Multiplying & Dividing
by 10, 100, 1000 …
© T Madas

34. Multiply and Divide by 10, 100, 1000, etc
43 x 10 =
430
8.6 x 10 = 86
17 x 100 =
1700
4.7 x 100 =
470
123 x 10 =
1230
1.25 x 10 =
12.5
58 x 1000 =
58000
2.813 x 1000 =
2813
570 ÷ 10 = 57
42 ÷ 10 =
4.2
8600 ÷ 10 =
860
465 ÷ 100 =
4.65
32000 ÷ 100 =
320
320 ÷ 100 =
3.2
4100 ÷ 100 = 41
4109 ÷ 100 =
41.09
© T Madas

35. Multiply and Divide by 10, 100, 1000, etc
66 x 10 =
660
2.6 x 10 = 26
31 x 100 =
3100
8.7 x 100 =
870
149 x 10 =
1490
1.75 x 10 =
17.5
10 x 1000 =
10000
4.394 x 1000 =
4394
360 ÷ 10 = 36
213 ÷ 10 =
21.3
7500 ÷ 10 =
750
465 ÷ 100 =
4.65
45000 ÷ 100 =
450
870 ÷ 100 =
8.7
3400 ÷ 100 = 34
8005 ÷ 100 =
80.05
© T Madas

36. Multiply and Divide by 10, 100, 1000, etc
131 x 10 =
1310
9.63 x 10 =
96.3
30 x 40 =
1200
5.52 x 100 =
552
20 x 50 =
1000
4.05 x 10 =
40.5
70 x 500 =
35000
9.506 x 1000 =
9506
930 ÷ 10 = 93
7.002 x 100 =
700.2
1800 ÷ 10 =
180
35 ÷ 10 =
3.5
2.7 x 10 = 27
809 ÷ 100 =
8.09
4.1 x 10 = 41
1876 ÷ 1000 =
1.876
© T Madas

37. Multiply and Divide by 10, 100, 1000, etc
16 x 10 =
160
8.65 x 10 =
86.5
123 x 10 =
1230
2.71 x 100 =
271
48 x 100 =
4800
2.25 x 10 =
22.5
5.8 x 10 = 58
4.916 x 1000 =
4916
570 ÷ 10 = 57
52 ÷ 100 =
0.52
8600 ÷ 10 =
860
375 ÷ 100 =
3.75
32 ÷ 10 =
3.2
665 ÷ 100 =
6.65
41 ÷ 10 =
4.1
792 ÷ 1000 =
0.792
© T Madas

38. Multiply and Divide by 10, 100, 1000, etc
151 x 10 =
1510
7.62 x 10 =
76.2
364 x 100 =
36400
1.92 x 100 =
192
9.2 x 10 = 92
4.85 x 10 =
48.5
7.83 x 10 =
78.3
6.906 x 1000 =
6906
930 ÷ 10 = 93
72 ÷ 1000 =
0.072
1800 ÷ 10 =
180
305 ÷ 100 =
3.05
17 ÷ 10 =
1.7
609 ÷ 1000 =
0.609
413 ÷ 10 =
41.3
1656 ÷ 1000 =
1.656
© T Madas

39. Multiply and Divide by 10, 100, 1000, etc
16.1 x 10 =
161
7.62 x 10 =
76.2
3.64 x 10 =
36.4
1.48 x 100 =
148
9.2 x 100 =
920
4.11 x 10 =
41.1
0.83 x 10 =
8.3
0.096 x 1000 = 96
930 ÷ 100 =
9.3
27 ÷ 1000 =
0.027
1825 ÷ 10 =
182.5
305 ÷ 1000 =
0.305
1.7 ÷ 10 =
0.17
609 ÷ 100 =
6.09
413 ÷ 10 =
41.3
696 ÷ =
0.0696
© T Madas

40. © T Madas