Year 4 Maths: Multiplying Decimals by 10, 100, 1000

Introduction to Multiplying Decimals

Hello Year 4! Today, we are going to learn about multiplying decimals by 10, 100, and 1000. This is an important skill that helps you work with numbers in real life, like money or measurements. Let’s break it down step by step!

What Happens When We Multiply Decimals?

When we multiply a decimal by 10, 100, or 1000, we are making the number bigger. But how do we do that? It’s simple! We move the decimal point to the right.

Key Rules:

1. Multiplying by 10: Move the decimal point one place to the right.
   • Example: $$2.5 \times 10 = 25.0$$ (which is the same as 25)
2. Multiplying by 100: Move the decimal point two places to the right.
   • Example: $$0.75 \times 100 = 75.0$$ (which is the same as 75)
3. Multiplying by 1000: Move the decimal point three places to the right.
   • Example: $$1.2 \times 1000 = 1200.0$$ (which is the same as 1200)

Visualisation

Imagine your decimal number is a car on a road. When you multiply by 10, 100, or 1000, it’s like driving down a road where the decimal point is a sign. The further you go, the more you grow!

Tips and Tricks

• Counting Places: Always count how many places you need to move the decimal point.
• Empty Spaces: If you run out of numbers when moving, you can fill empty spaces with zeros.
• Check Your Work: After multiplying, read the number to see if it makes sense.

Practice Questions

Easy Level Questions (1-20)

1. $$0.3 \times 10 = ?$$
2. $$1.5 \times 10 = ?$$
3. $$2.6 \times 10 = ?$$
4. $$0.2 \times 100 = ?$$
5. $$3.0 \times 100 = ?$$
6. $$4.5 \times 100 = ?$$
7. $$0.04 \times 100 = ?$$
8. $$0.6 \times 1000 = ?$$
9. $$5.5 \times 1000 = ?$$
10. $$0.005 \times 1000 = ?$$
11. $$2.1 \times 10 = ?$$
12. $$0.9 \times 10 = ?$$
13. $$0.8 \times 100 = ?$$
14. $$1.2 \times 100 = ?$$
15. $$0.7 \times 1000 = ?$$
16. $$0.03 \times 100 = ?$$
17. $$0.1 \times 10 = ?$$
18. $$0.2 \times 1000 = ?$$
19. $$4.0 \times 10 = ?$$
20. $$3.3 \times 100 = ?$$

Medium Level Questions (21-40)

21. $$0.45 \times 10 = ?$$
22. $$1.32 \times 10 = ?$$
23. $$2.75 \times 100 = ?$$
24. $$0.68 \times 100 = ?$$
25. $$3.14 \times 100 = ?$$
26. $$0.56 \times 1000 = ?$$
27. $$1.8 \times 1000 = ?$$
28. $$0.004 \times 1000 = ?$$
29. $$0.25 \times 10 = ?$$
30. $$4.56 \times 10 = ?$$
31. $$0.78 \times 100 = ?$$
32. $$2.34 \times 100 = ?$$
33. $$5.67 \times 1000 = ?$$
34. $$0.09 \times 1000 = ?$$
35. $$3.45 \times 10 = ?$$
36. $$1.11 \times 100 = ?$$
37. $$0.007 \times 100 = ?$$
38. $$2.88 \times 1000 = ?$$
39. $$0.12 \times 1000 = ?$$
40. $$1.6 \times 100 = ?$$

Hard Level Questions (41-60)

41. $$2.56 \times 10 = ?$$
42. $$3.141 \times 10 = ?$$
43. $$0.789 \times 100 = ?$$
44. $$1.234 \times 100 = ?$$
45. $$0.567 \times 1000 = ?$$
46. $$0.00123 \times 1000 = ?$$
47. $$4.567 \times 10 = ?$$
48. $$2.222 \times 100 = ?$$
49. $$0.009 \times 1000 = ?$$
50. $$1.005 \times 1000 = ?$$
51. $$0.444 \times 10 = ?$$
52. $$5.678 \times 1000 = ?$$
53. $$0.0005 \times 1000 = ?$$
54. $$3.3 \times 1000 = ?$$
55. $$0.250 \times 100 = ?$$
56. $$2.999 \times 10 = ?$$
57. $$0.123 \times 1000 = ?$$
58. $$4.4 \times 100 = ?$$
59. $$0.006 \times 100 = ?$$
60. $$5.5 \times 1000 = ?$$

Answers and Explanations

Easy Level Answers

1. 3.0
2. 15.0
3. 26.0
4. 20.0
5. 300.0
6. 450.0
7. 4.0
8. 600.0
9. 5500.0
10. 5.0
11. 21.0
12. 9.0
13. 80.0
14. 120.0
15. 700.0
16. 3.0
17. 1.0
18. 200.0
19. 40.0
20. 330.0

Medium Level Answers

21. 4.5
22. 13.2
23. 275.0
24. 68.0
25. 314.0
26. 560.0
27. 1800.0
28. 4.0
29. 2.5
30. 45.6
31. 78.0
32. 234.0
33. 5670.0
34. 90.0
35. 34.5
36. 111.0
37. 0.7
38. 2880.0
39. 120.0
40. 160.0

Hard Level Answers

41. 25.6
42. 31.41
43. 78.9
44. 123.4
45. 567.0
46. 1.23
47. 45.67
48. 222.2
49. 9.0
50. 1005.0
51. 4.44
52. 5678.0
53. 0.5
54. 3300.0
55. 25.0
56. 29.99
57. 123.0
58. 440.0
59. 0.6
60. 5500.0

Now, go ahead and try these questions on your own. Remember, practice makes perfect! Good luck, Year 4!