Unit 4: Multiplication

# Topic B: Multiplying by 10, 100 and 1 000

When multiplying by 10, 100, 1000, 10000, etc., place as many zeros to the right of the number as there are zeros in the 10, 100, 1000, etc..

To multiply by 10 put one zero after the number. To multiply by 100 put two zeros after the number.

To multiply by 1000 put three zeros after the number.

Example: 4 × 100 =

100 has two zeroes. Put two zeroes after the number.

4 × 100 = 400

Exercise One

1. 10 × 2 =
2. 9 × 100 =
3. 100 × 3 =
4. 1 × 1000 =
5. 6 × 100 =
6. 10 × 7 =
7. 100 × 10 =
8. 2 × 10 =
9. 5 × 10 =
10. 1000 × 1 =
11. 0 × 10 =
12. 1000 × 9 =
13. 4 × 1000 =
14. 10 × 0 =
15. 100 × 8 =
16. 3 × 1000 =
17. 10 × 5 =
18. 7 × 1000 =
19. 1000 × 6 =
20. 8 × 10 =
21. 100 × 4 =
22. 1 × 100 =
23. 1000 × 3 =
24. 10 × 100 =

Answers to Exercise One

1. 20
2. 900
3. 300
4. 1000
5. 600
6. 70
7. 1000
8. 20
9. 50
10. 1000
11. 0
12. 9000
13. 4000
14. 0
15. 800
16. 3000
17. 50
18. 7000
19. 6000
20. 80
21. 400
22. 100
23. 3000
24. 1000

Exercise Two

Find the products. Check your work using the answer key at the end of the exercise.

1. 100 × 9 =
2. 10 × 1000 =
3. 10 × 9 =
4. 1000 × 8 =
5. 6 × 10 =
6. 100 × 0 =
7. 3 × 100 =
8. 10 × 1 =
9. 100 × 1 =
10. 5 × 1000 =
11. 8 × 100 =
12. 1000 × 4 =
13. 9 × 10 =
14. 10 × 100 =
15. 10 × 6 =
16. 5 × 100 =
17. 1 × 10 =
18. 9 × 1000 =
19. 100 × 6 =
20. 10 × 8 =
21. 3 × 10 =
22. 1000 × 0 =
23. 2 × 1000 =
24. 1000 × 7 =

Answers to Exercise Two

1. 900
2. 10000
3. 90
4. 8000
5. 60
6. 0
7. 300
8. 10
9. 100
10. 5000
11. 800
12. 4000
13. 90
14. 1000
15. 60
16. 500
17. 10
18. 9000
19. 600
20. 80
21. 30
22. 0
23. 2000
24. 7000

# Topic B:  Self-Test

Mark    /18    Aim 15/18

1. Find the products.  Be sure to check your answers. (6 marks)
1. 3 × 10 =
2. 6 × 100 =
3. 8 × 1000 =
4. 7 × 1000 =
5. 4 × 100 =
6. 5 × 10 =
2. Find the products. Be sure to check your answers. (6 marks)
1. 10 × 10 =
2. 1000 × 9 =
3. 100 × 10 =
4. 100 × 2 =
5. 10 × 0 =
6. 1000 × 4 =
3. Find the products.  Be sure to check your answers. (6 marks)
1. 10 × 6 =
2. 1000 × 7 =
3. 100 × 4 =
4. 5 × 1000 =
5. 8 × 10 =
6. 10 × 100 =

1. 30
2. 600
3. 8000
4. 7000
5. 400
6. 50
1. 100
2. 9000
3. 1000
4. 200
5. 0
6. 4000
1. 60
2. 7000
3. 400
4. 5000
5. 80
6. 1000