Cost Estimating Methods Tutorial
Cost Estimating Methods Tutorial

Rounding Numbers

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Rounding Numbers : Rounding makes numbers that are easier to work with in your head. •Rounded numbers are only approximate. •An exact answer generally can not be obtained using rounded numbers. •Now round to get a answer that is close, but that does not have to be exact.
How to round numbers
• Make the numbers that end in 1 through 4 ( for tens) , 01 to 49 (for hundred),001 to 499 (for thousand) and 0001 to 4999 (for 10 thousand ) and so on, into the next lower number that ends in 0,00,000,000 and so on.

• For example: 1) 74 rounded to the nearest ten would be 70 as 4 is less than 5.
2) 138 → 138 → 140 (as 8>5 so 8 becomes zero and previous number will increase by 1) • Numbers that end in a digit of 5,50,500,5000 or more should be rounded up to the next even ten, hundred, thousand and 10 thousand. The number 88 rounded to the nearest ten would be 90.
Example : 1) Round 2387 to the nearest 10
Solution : In 2387
As 7 > 5 so 7 becomes zero and previous number will increase by 1.
2387 ----> 2390

Example : 2) Round 18,649 to the nearest 100.
Solution : In 18,649
49 < 50 so 49 becomes 00 and previous number remains unchanged.
18,649 ----> 18,600

Round Down Decimals :
This rounded method works the same way when they tell you to round to a certain named place, such as "the hundredths place".The decimal places count off to the right in the same order as the counting numbers count off to the left.
For decimal places, you don't have a "oneths", but you do have the other fractions: (decimal point) (tenths) (hundredths) (thousandths) (ten-thousandths)..

Example Round 2.596 to the hundredths place.
Solution: The hundredths place is two decimal places, so I'll count off two decimal places, and round according to the third decimal place:
2.59 | 6
Since the third decimal place contains a 6, which is greater than 5, I have to round up. But rounded up a 9 gives a 10. In this case, I round the 59 up to an 60:

Example : Round 909 thousandths to tenths.
Solution : 909 thousandths = 0.909
The tenth place is two decimal places, so I will count off two decimal places, and round according the the 2nd decimal place place:
0.9 | 0
Since the 2nd decimal contains 0, which is less than 5 so the previous number will remain as it is.
∴ 0.909 becomes 0.9

Number System

International System of Numeration
Roman Numbers
Rounding Numbers