Rounding a number means reducing the number to a simple number(mainly to a multiple of ten, hundred, thousand etc..) while keeping its value close enough to the original number. In other words, it is nothing but to write down the approximate value of a number in a way that performing operations using the number becomes an easy process. There are several ways to round the numbers. Recall the concept of the place value system.
Consider a number 78. You can round 78 nearest to its tens. When you round 78 to the nearest tens, we get 80.
Why can’t 78 be rounded to 70? There are some rules to be followed when you round the number.
Rules for Rounding
The standard rules followed to round a number are as follows:
First step is to understand which place you are required to round the number. You apply the steps on the digit that follows that place.
When you stop at a number less than 5, you will move back to 0; when you stop at number greater than or equal to 5, you will reach to 10.
A number can be rounded to the nearest tens, hundreds, or thousands. Let us consider an example 1349.
Example 1: Round the following numbers nearest to tens.
Solution: To round the numbers nearest to their tens, look at the digit in the units place.
Example 2: Round the following numbers nearest to hundreds.
Solution: To round the numbers nearest to their hundreds, look at the digit in the tens place.
Example 3: Round the following numbers nearest to tens, hundreds and thousands.
Solution: The given numbers can be rounded as shown in the table below
Rounding numbers is an integral part of our daily lives.
George Greenhill proceeded to Christ’s Hospital School, where he received the Thompson Mathematical Gold Medal, and then to St John’s College, Cambridge, in 1866. He was a Pitt Club exhibitioner, then a Somerset exhibitioner, a foundation scholar, a London University scholar, and lastly a Whitworth engineering scholar there. In the final examinations of 1870, he was ranked Second Wrangler and shared the Smith’s Prize with R Pendlebury, the First Wrangler.
Greenhill specialized in elliptic functions. Their applications to dynamics, hydrodynamics, elasticity, and electrostatics piqued his interest.
Greenhill’s investigation of the maximum length a cylinder can have before it bends under its own weight was a significant contribution to the theory of elasticity. Calculating the greatest height a tree may reach was one of his applications.