Multiplication of 2 numbers that are near to 100 or 1000

This tip is suitable for multiplying two numbers that are near to 100. For example, 103 x 104 and 97 x 98.

Example 1:

To calculate 103 x 104:

1. Add the the ones from the multiplicand to the multiplier.
   103 + 4 = 107.


2. Multiply the ones from the multiplier with the ones from the multiplicand.
   3 x 4 = 12.


3. Concatenate the results from step 1 and 2. Therefore, 103 x 104 = 10712.

Example 2:

To calculate 1005 x 1002:

1. Add the the ones from the multiplicand to the multiplier.
   1005 + 2 = 1007.


2. Multiply the ones from the multiplier with the ones from the multiplicand. Prepend a zero to the result.
   5 x 1 = 010.


3. Concatenate the results from step 1 and 2. Therefore, 1005 x 1002 = 1007010.

Example 3:

To calculate 97 x 98:

1. Subtract from 10, the ones from multiplicand.
   10 - 8 = 2.


2. Subtract from multiplier, the result from step 1.
   97 - 2 = 95.


3. Subtract from 10, the ones from multiplier.
   10 - 7 = 3.


4. Multiply the result from step 3 with the result from 1. Prepend a zero.
   2 x 3 = 06.


5. Concatenate the results from step 2 and step 4. Therefore, 97 x 98 = 9506.

Example 4:

To calculate 993 x 995:

1. Subtract from 10, the ones from multiplicand.
   10 - 5 = 5.


2. Subtract from multiplier, the result from step 1.
   993 - 5 = 988.


3. Subtract from 10, the ones from multiplier.
   10 - 3 = 7.


4. Multiply the result from step 3 with the result from 1. If you get a one digit number, prepend two zeroes, otherwise prepend just one zero.
   5 x 7 = 035.


5. Concatenate the results from step 2 and step 4. Therefore, 993 x 995 = 988035.

Exercise:

If domain name is cost $9.90 each, what is the cost if you want to buy 92 domain?