Rounding numbers coverts large numbers and decimal numbers to simpler forms which are then useful to solve or express in a given question. This concept is commonly used in many word problem and different calculations. Rounding to the tenth’s place is rounding of a decimal number to the nearest one decimal space. Rounding to the hundredth’s place is rounding a decimal number to the nearest two decimal spaces. Rounding to the thousandth’s place is rounding a decimal number to the nearest three decimal spaces and so on.
Example 1: The price of each book is $ 15.78. If the shopkeeper sold 13 copies. Find the total money earned by the shopkeeper.
Solution: Price of each book = $ 15.78.
Number of copies sold by the shopkeeper = 13.
The money earned by the shopkeeper = 13 * 15.78 = $ 205.14.
Rounding the decimal number to the nearest whole number.
Hence the money earned by the shopkeeper = $ 205.
Example 2: There are 15 children in the class. 7 of them buy cupcakes and the remaining buy cookies. Each cookie costs $ 1.89 and cupcake costs $2.24. How much did the class spend (round to a whole number)?
Solution: Price of each cookie = $ 1.89.
Price of each cupcake = $ 2.24.
Number of students brought cupcakes = 7
Number of students brought cookies = 8.
Amount spent on cupcakes = 7 * 1.89 = $ 13.23
Amount spent on cookies = 8 * 2.24= $ 17.92
The total amount spent = $ 31.15 (Rounding the decimal)
Hence, total amount spent = $ 31.