Add, subtract and multiply whole numbers with a worked column-by-column trace, using exact big-integer arithmetic.
Result
How to use this tool
Enter the numbers as digits, with a minus sign if negative.
Pick addition, subtraction or multiplication.
Read the exact result and its digit count.
Work through the column-by-column steps to verify the answer.
Formula & worked example
1,234 + 5,678 = 6,912: units 4 + 8 = 12 (write 2, carry 1), tens 3 + 7 + 1 = 11 (write 1, carry 1), and so on to the final answer.
Limitations — read this before you rely on it
Whole numbers only; no decimals, fractions or division. Extremely long inputs produce extremely long traces.
Frequently asked questions
The column method taught in school: work digit by digit from the right, carrying and borrowing as needed.
Yes. It uses exact big-integer arithmetic, so numbers far beyond normal calculator limits stay exact.
No. This tool is for whole numbers only; use a decimal calculator for fractional values.
Multiply by each digit of the second number, shift each partial product by its place value, then add them.
So the answer can be checked and the method learned, not just trusted.