Here are the methods you can use when multiplying a whole number and a decimal. In multiplying a whole number, you can just do the normal multiplication process and the product would still be a whole number. In multiplying a decimal, it becomes different because the decimal points will affect the product. In multiplying decimal, each time we multiply by a power of 10, the decimal point is moved one place to the right. When multiplying a decimal by a whole number, placement of the decimal point is very important. When a given number has 2 decimal places, the product must also have two decimal places. Hope this explanation helps.