Can some one please tell me the rules to rounding off the digits? I am having confusion on how to round of to nearest digits.

say 1.485 -> rounded to nearest hundredths and nearest tenths

can some one help with the rounding of rules?

Sure! Let's think about rounding. If I am rounding to a particular place, I only must consider the place to the right of the place we are interested in. For example, if I have 650 and am rounding to the nearest hundred, I consider the tens place. It has a 5, and I round up with a 5. So I round 650 to 700.

If I am rounding 43 to the tens place, I consider the ones place. It has a 3, so I round down. 43 rounds to 40.

Now, let's look at this one. "tenths" is the place to the right of the point (the 4 is there); "hundredths" is two places to the right (the 8 is there). The 5 is in the thousandths place.

Let's round 1.485 to the tenths place. We only need to consider the number in the hundredths place, 8. Round up. 1.485 rounds to 1.5.

Now let's round 1.485 to the hundredths place. We must consider the number in the thousandths place, 5. Round up. 1.485 rounds to 1.49.

Please let me know if I can offer further clarification.

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Jamie Nelson
ManhattanGMAT Instructor

Hi,

How do you round-off the following and the likes of it:

-round off 290 miles to the nearest 10 miles
-round off 12 gallons to the nearest gallon

they are already rounded off..

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Tim Sanders
Manhattan GMAT Instructor

Here's the general rule for rounding:

If the number you are rounding is followed by 5, 6, 7, 8, or 9, round the number up. Example: 38 rounded to the nearest ten is 401

If the number you are rounding is followed by 0, 1, 2, 3, or 4, round the number down. Example: 33 rounded to the nearest ten is 30

Rounding fractions works exactly the same way as rounding whole numbers. The only difference is that instead of rounding to tens, hundreds, thousands, and so on, you round to tenths, hundredths, thousandths, and so on.

7.8199 rounded to the nearest tenth is 7.8
1.0621 rounded to the nearest hundredth is 1.06
3.8792 rounded to the nearest thousandth is 3.879

.

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Tim Sanders
Manhattan GMAT Instructor

hi

what's the rule for rounding times? I saw a question recently where it said "labour for car repairs was $45 and hour, rounded to the nearest 1/2 hour". The question said all the car repairs took 3.5 hours. what if it took 3.75 hours, would I round to 4 hours, or to 3 1/2 hours?

thanks

We would round 3.75 to 4 hours, since it is exactly halfway between 3.5 and 4 hours and we always round up when we are halfway between.

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Jamie Nelson
ManhattanGMAT Instructor