When you approximate a measure it means the measure is very close to precise, but not exact. With the approximation process, we can evaluate any number or getting a rounding of a number to its nearest place value. An approximate measure is good enough to allow to us the measure to relative to whatever task we are performing with the measure. We often use this when we are gauging the length of time trips in the car. I always say that it takes an hour to get to work, but it is more like fifty-four minutes. When you do that five times a week, it sure feels like an hour.

If the given number's last digit is less than five (5), you will round the lower number that ends with zero (0). If the given number is greater than 5, you will add 1 to the digit that you have rounded up. It means, in this case, you will round up the number rather than rounding the lower number. These worksheets explain how to approximate measurements by rounding the answers to different values according to the directions. Calculators can be used to make them go by quicker, but hand calculations are never over rated. E.g., # 1 – 240 rounded to the nearest tens category is 240. You can see here the place of the value of the digit in the ones place is less than (5). In this case, you will round off the number zero (0). E.g., # 2 – you will round 2589 to the nearest hundred that is 2600. You can see hundreds place value that is five (5). In this case, you will round it up with the addition of 1 to that digit.