Multiplying Any Number With 111, 1111, etc using Speed Mathematics
If you have not gone through to the topic Multiplication by 11 , please go through that topic before proceeding further.
Table of Contents
Example 1
Calculate 752 * 111
Solution
Step 1: Three ones are there in 111. So we have to keep adding maximum to the depth of three. So the digits in the answer will be 7 , 7+5 , 7+5+2, 5+2, 2
=> 7, 12, 14, 7, 2
Step 2: If the sum of digits is a two digit number, the left digit is considered as a carry digit, In this case, 1 is carry digit for 12 and 2 is written. 1 is carry digit for 14 and 4 is written. So this can be written as
7, 2(carry=1), 4(carry=1), 7, 2
Step 3: Carry digits will be added to its left digit.
=> 7+1, 2+1, 4, 7, 2
=> 8, 3, 4, 7, 2
Step 4: Yes, you have got the answer now . Just put these digits together.
i.e., the answer is 83472
Example 2
Calculate 57 * 111
Solution
Step 1: Three ones are there in 111. So we have to keep adding maximum to the depth of three. Also to make 57 compatible with 3 digits, it is written as 057. So the digits in the answer will be 0 , 0+5 , 0+5+7, 5+7, 7
=> 0, 5, 12, 12, 7
Step 2: If the sum of digits is a two digit number, the left digit is considered as a carry digit, In this case, 1 is carry digit for 12 and 2 is written. So this can be written as
0, 5, 2(carry=1), 2(carry=1), 7
Step 3: Carry digits will be added to its left digit.
=> 0, 5+1, 2+1, 2, 7
=> 0, 6, 3, 2, 7
Step 4: Yes, you have got the answer now . Just put these digits together.
i.e., the answer is 06327 or 6327
Example 3
Calculate 1257 * 1111
Solution
Step 1: Four ones are there in 1111. So we have to keep adding maximum to the depth of four. So the digits in the answer will be 1, 1+2 , 1+2+5, 1+2+5+7, 2+5+7, 5+7, 7
=> 1, 3, 8, 15, 14, 12, 7
Step 2: If the sum of digits is a two digit number, the left digit is considered as a carry digit, In this case, 1 is carry digit for 15 and 5 is written. 1 is carry digit for 14 and 4 is written. 1 is carry digit for 12 and 2 is written. So this can be written as
1, 3, 8, 5(carry=1), 4(carry=1), 2(carry=1), 7
Step 3: Carry digits will be added to its left digit.
=> 1, 3, 8+1, 5+1, 4+1, 2, 7
=> 1, 3, 9, 6, 5, 2, 7
Step 4: Yes, this is the answer . Just put these digits together.
i.e., the answer is 1396527.
Multiplying Any Number With 111, 1111, etc using Speed Mathematics