Multiplying Decimals Calculator

This calculator multiplies decimal numbers and sets out the working rather than just the answer. Enter two numbers, or a list of up to ten separated by commas, and it drops the decimal points, multiplies the whole numbers in a written column, adds up the decimal places in the factors and counts that many back into the product. It also flags the trailing zeros the rule leaves behind, checks the answer against a rough estimate and explains why moving the points is allowed. The arithmetic runs on digit strings instead of floating point, so a product like 1.1 times 2.2 comes out as 2.42 rather than 2.4200000000000004.