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
 10 × 2 =
 9 × 100 =
 100 × 3 =
 1 × 1000 =
 6 × 100 =
 10 × 7 =
 100 × 10 =
 2 × 10 =
 5 × 10 =
 1000 × 1 =
 0 × 10 =
 1000 × 9 =
 4 × 1000 =
 10 × 0 =
 100 × 8 =
 3 × 1000 =
 10 × 5 =
 7 × 1000 =
 1000 × 6 =
 8 × 10 =
 100 × 4 =
 1 × 100 =
 1000 × 3 =
 10 × 100 =
Answers to Exercise One
 20
 900
 300
 1000
 600
 70
 1000
 20
 50
 1000
 0
 9000
 4000
 0
 800
 3000
 50
 7000
 6000
 80
 400
 100
 3000
 1000
Exercise Two
Find the products. Check your work using the answer key at the end of the exercise.
 100 × 9 =
 10 × 1000 =
 10 × 9 =
 1000 × 8 =
 6 × 10 =
 100 × 0 =
 3 × 100 =
 10 × 1 =
 100 × 1 =
 5 × 1000 =
 8 × 100 =
 1000 × 4 =
 9 × 10 =
 10 × 100 =
 10 × 6 =
 5 × 100 =
 1 × 10 =
 9 × 1000 =
 100 × 6 =
 10 × 8 =
 3 × 10 =
 1000 × 0 =
 2 × 1000 =
 1000 × 7 =
Answers to Exercise Two
 900
 10000
 90
 8000
 60
 0
 300
 10
 100
 5000
 800
 4000
 90
 1000
 60
 500
 10
 9000
 600
 80
 30
 0
 2000
 7000
Topic B: SelfTest
Mark /18 Aim 15/18
 Find the products. Be sure to check your answers. (6 marks)
 3 × 10 =
 6 × 100 =
 8 × 1000 =
 7 × 1000 =
 4 × 100 =
 5 × 10 =
 Find the products. Be sure to check your answers. (6 marks)
 10 × 10 =
 1000 × 9 =
 100 × 10 =
 100 × 2 =
 10 × 0 =
 1000 × 4 =
 Find the products. Be sure to check your answers. (6 marks)
 10 × 6 =
 1000 × 7 =
 100 × 4 =
 5 × 1000 =
 8 × 10 =
 10 × 100 =
Answers to Topic B Self Test

 30
 600
 8000
 7000
 400
 50

 100
 9000
 1000
 200
 0
 4000

 60
 7000
 400
 5000
 80
 1000