Indian Subtraction Trick (Complement Method) Calculator

Subtract numbers using the Indian complement method. See each step broken down so you can do borrow-free subtraction in your head.

Input

Enter a minuend and a subtrahend to see the Indian complement method for subtraction step by step.

Minuend (number subtracted from)

Subtrahend (number to subtract)

Enter whole numbers of 0 or more. The subtrahend must be less than or equal to the minuend.

Difference of 523 minus 268

255

Base

1,000

Complement of subtrahend

732

Minuend plus complement

1,255

Building the complement

The complement is the base 1,000 minus the subtrahend. Subtract each digit from 9 and the last digit from 10.

Position	Digit	Rule	Complement digit
1	2	9 minus 2	7
2	6	9 minus 6	3
3	8	10 minus 8	2

Step by step

Choose 1,000 as the smallest base larger than the subtrahend 268.

Find the complement: 1,000 minus 268 equals 732.

Add the complement to the minuend: 523 plus 732 equals 1,255.

Finally subtract the base: 1,255 minus 1,000 equals 255.

Minuend plus complement minus base equals minuend minus subtrahend, turning borrowing into addition.

The base is the smallest power of ten that is larger than the subtrahend, such as 10, 100 or 1000.
The complement of the subtrahend equals the base minus the subtrahend. Subtract each digit from 9 and the last digit from 10 to find it quickly.
The difference is found by adding the complement to the minuend and then subtracting the base. This replaces borrowing with addition.
Inputs must be whole numbers of 0 or more, and the subtrahend must be less than or equal to the minuend.

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