Summarize the following:
This is the “to the nearest” value. This might be explicitly stated (for example, “The building was measured to the nearest foot.”), but it doesn’t have to be. To determine the measuring unit, just look at what place value the measurement is rounded to. For example, if the measured length of a building is stated as 357 feet, you know that the building was measured to the nearest foot. So, the measuring unit is 1 foot. The maximum possible error is 12{\displaystyle {\frac {1}{2}}} the unit of measure. You might see it listed as ±{\displaystyle \pm } a number. For example, if the unit of measure is a foot, the maximum possible error is .5 ft. So you might see that the measurement of a building is 357±.5ft{\displaystyle 357\pm .5ft}. This means that the actual value of the building’s length could be .5 ft less or .5 ft more than the measured value. If it was any less/more, the measured value would have been 356 or 358 feet. Since absolute error is always positive, take the absolute value of this difference, ignoring any negative signs. This will give you the absolute error. For example, if you find the measurement of a building to be 357±.5ft{\displaystyle 357\pm .5ft}, the absolute error is .5 ft.

Summary:
Determine the measuring unit. Determine the maximum possible error. Use the maximum possible error as the absolute error.