10-Mar-08 (Created: 10-Mar-08) | More in 'Book5'

02. Multiplication of numbers with ending zeroes

Rule

When you multiply two numbers with any of them having ending zeroes, you cad do this:

1. Count the number of zeroes that are there at the end of both numbers. Say there are 3 all together.

2. Remove them from both numbers

3. Look at the remaining two numbers.

4. Multiply those numbers

5. Now put back the combined number of removed zeroes at the end of the answer in step 4

Example

Take the following multiplication

20 x 700

Now let's see how each of the above steps apply

1. Count the number of zeroes that are there at the end of both numbers. 3 all together One in 20 and two in 700. Together they make three.

2. Remove them from both numbers. 2 x 7

3. Look at the remaining two numbers. 2 and 7

4. Multiply those numbers 2 x 7 = 14

5. Now put back the combined number of removed zeroes at the end of the answer in step 4. 14000. See how the 3 zeroes are added to 14 making 14,000.

Example 2

250 X 10 = 

how many zeroes together: 2 or 00
multiply the remaining numbers: 25 X 1 = 25
Final answer: 2500

Your Try 1

20 X 10 = 

how many zeroes together:

multiply the remaining numbers:

Final answer:

Your Try 2

250 X 40 = 

how many zeroes together:

multiply the remaining numbers:

Final answer:

Your Try 3

80 X 90 = 

how many zeroes together:

multiply the remaining numbers:

Final answer:

Your Try 4

20 X 10 = 

60 x 80 =

70 X 600 =