Decimals are used in everyday situations. For example:
You can measure a person's height using inches or centimeters and then record the results as decimal. So 65 inches is 5.5 feet and 102 cm is 1.02 meters.
You can measure time it takes a person to run a race, and then record the results as decimal 4.5 minutes.
You can use decimals to find the cost of items that you buy at the store.
Addition/Subtraction:
Place the numbers so that the decimal points are vertically aligned.
Add or subtract as indicated.
Multiplication:
Ignore the decimal points and write the numbers down for multiplication.
Multiply decimal numbers just as you multiply whole numbers.
Then, add up the number of decimal places in both numbers to find the position of the decimal point in the product by counting from the right side.
Division:
Perform regular division ignoring the decimal points.
Place the decimal in the quotient when carrying down the number.