Long Multiplication Calculator

This multiplies two whole numbers the way it is done on paper, and shows the working rather than just the answer. Enter the two numbers, up to fifty digits each, and it returns the product, one partial product for every digit of the second number, the column those rows are added up in, and the carry behind each single digit step. The arithmetic is done in arbitrary precision, so factors far past anything a spreadsheet holds exactly still come back correct to the last digit. A casting out nines check is printed with the answer, so the result can be verified without working it again. Decimal points are not accepted here, only whole numbers.