No mathematician likes working with a long string of decimals, so they will often use a technique called "rounding" or "estimating" to make these numbers easier to work with.It's a lot like rounding a whole number, just find the place value you need to round to and look at the digit to the right.Round up if it's five or higher.Round down if it's below five.
Step 1: Understand the concept of place.
The different digits represent different amounts in a number.The "8", "7", and "2" all represent hundreds, while the "1" represents thousands.The numbers to the right of the point are fractions of one.The places to the right of the decimal point are named after the whole number of places.For ten-thousandths, the first number to the right represents the second and third, and so on."8" is the number of ten-thousandths, while "7", "5", and "3" all have the same number.
Step 2: The place you need to round to is the decimal place.
The first thing you need to do is figure out which decimal place you're going to round it to.If you're doing schoolwork, this information is usually given to you, often the problem will say something like, "round the answer to the nearest tenth/hundredth/thousandth."If you are asked to round to the nearest thousandth in the number, you would start by finding the place.The second "8" (12.989) is the one you want, because the spaces to the right represent tenth, hundredths, thousandth, and ten-thousandth.The same thing as "round to the nearest thousandth" can be said if instructions tell you exactly which decimal place to round to.
Step 3: The space to the right has a number in it.
The place you're rounding to has a decimal place to the right of it.You can round up or down based on the number in this place.If you look at the number to the right of this, you'll see that it's the final number (12.988).
Step 4: Round up the number if it's greater than or equal to five.
Round it up if the place you're rounding to is followed by 5, 6, 7, 8, or 9.If you want to get rid of the digits after it, make that decimal place one value greater.The rounded value becomes, since the final 9 is higher than 5.The digits should be dropped after the rounded decimal place.
Step 5: Round down the number if it is less than five.
Round it down if the place you're rounding to is followed by a 4, 3, 2, 1, or 0.Leave the rounded digit as it is and get rid of the digits after that.The final 9 is not 4 or lower, so you wouldn't go down.You could round it down to 12.988 if you were working with it.Does the process seem familiar?The way you round whole numbers is the same as the way the decimal point is used.
Step 6: Round to a whole number using the same technique.
A rounding task is to round a number to the nearest whole number.The rounding technique should be used in this case.Look at the number to the right if you want to start.Round up if this number is greater than 5.Round down if it is 4 or lower.The point in the middle doesn't change anything.If you needed to round the example number from earlier (12.9889) to the nearest whole number, you would start by looking at the ones place.You would round up if the "9" to the right is greater than 5.You don't need the decimal point anymore since you've gotten a whole number answer.
Step 7: Special instructions should be looked out for.
The directions for rounding will work well.Before you use the normal rounding rules, make sure to follow the special directions.If you receive the instructions "Round 4.59 to the nearest tenth", you'd round the 5 in the tenths place down even though the 9 would normally round it up.This would give you something.If you're told to round 180.1 to the nearest whole number, you would round even if you normally round down.
Step 8: To the nearest hundredth.
The solution can be seen below.Find the hundredths place first.There are two spaces to the right of the number.Round down the number to 45.78 since 3 is less than 5.This gives an answer.
Step 9: The round ended at the third place.
"Third decimal place" means to count three spaces to the right of the decimal point."thousandths place" is the same thing.Find the third decimal place.This is 6.199.The number is to the right.This is 6.077.Round up when 9 is greater than 5.This gives an answer.
Step 10: The round ended at the nearest tenth.
Zeroes count as numbers less than four if you use the "0" here.Find the tenths place is the solution.This is a new date.There is a number to the right.This time is 11.9.Round down since 0 is less than 5.The answer is given by this.
Step 11: The round was 8.7 to the nearest whole number.
The same way as rounding positive numbers, rounding negative numbers is the same thing.The ones place is to be found.Look at the number to the right.It's -8.Round up when 7 is greater than 5.This gives an answer.The negative sign should be left as is.