Answer:
A. To multiply decimals, first multiply as if there is no decimal. Next, count the number of digits after the decimal in each factor. Finally, put the same number of digits behind the decimal in the product.
B. We use decimals everyday while dealing with money, weight, length etc. Dicemal numbers are used in situations where more precision is required than the whole numbers can provide.
For example, when we calculate our weight on the weighing machine, we do not always find the weight equal to a whole number on the scale.
