How do you find 115.45 rounded to the tenth?

Answer 1

Each number after the decimal point stands for one zero - so the 10 place would be the first number after the decimal point.

To round a number, you look at the very next number after whichever number you're trying to round. If that number is 5 or more (half of 10 - see how the zeroes work?) - then you round your number up to the next whole number. If that next number is less than 5 you keep your number the same.

This number is 115.45 so the 4 is the number you want to round because it it in the 10's place. Now, is the number immediately after that 4 a 5 or more? Yes it is, so you round the 4 to the next whole number to make 115.5.

Answer 2

It is 115.4

Most schools teach you to always round 5 up (so the answer would be 115.5) but, while this is a simple rule to teach, it is not really correct. Under this rule:

• if the following digit is 0 you don't round;

• if the following digit is 1, 2, 3 or 4 you round down; and

• if the following digit is 5, 6, 7, 8 or 9 you round up.

As a result you are more likely to round up than round down and that introduces an upward bias into your calculations.

The IEEE (Institute of Electronic and Electrical Engineers) standard 754 is to round 5 up or down so that the new last digit is even. See link for more: //en.wikipedia.org/wiki/Rounding#Round_half_to_even