Step-by-step decimal multiplication explained
Supports up to 3 decimal places per number — e.g. 12.5 × 3.4 or 1.125 × 0.75.
Multiplying decimal numbers follows the same column method as whole number multiplication — with one important extra step at the end. First, you temporarily ignore the decimal points and multiply the numbers as if they were whole numbers. Then, you count up the total number of decimal places in both original numbers and insert the decimal point that many places from the right of your answer.
Carrying out long multiplication with decimal points in place is unnecessarily complicated. By treating the numbers as whole numbers first, you can use the exact same column method you already know. The decimal rule at the end is a reliable shortcut: if one number has 1 decimal place and the other has 2, your answer will always have 3 decimal places total.
Sometimes after placing the decimal point, the answer starts with a zero to the left of it — for example 0.36 rather than .36. This leading zero is important: it makes it clear that the number is less than one and prevents misreading. Unfold Math always shows it, and you should too when writing your answers.
Before tackling decimals, make sure column multiplication with whole numbers feels comfortable. When you work with decimals, count the decimal places carefully before you start — write them down if it helps. A common mistake is miscounting and placing the decimal point one position too far left or right.
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