Mathematics ACT Aspire Practice Test

What notation is used to indicate a repeating decimal?

1. A parentheses around the digits

2. A dot above the repeating digits

3. A bar over the repeating digits

4. A line underneath the entire number

The correct answer is: A bar over the repeating digits

The notation used to indicate a repeating decimal involves placing a bar over the digits that repeat. This method clearly identifies which part of the decimal is repetitive, making it easy to understand the value of the number. For example, in the repeating decimal 0.666..., the bar would be placed over the "6" to represent it as \( 0.\overline{6} \). Using a bar over the digits is a widely accepted mathematical convention, particularly useful in fractional representations and calculations involving repeating decimals. This notation helps to avoid confusion and clearly indicates the beginning and end of the repeating segment. Other notations, like placing parentheses around the digits or dots above them, are less commonly accepted or used in specific educational contexts but are not as standardized as the bar notation. The incorrect options may not convey the information as clearly or may differ in meaning based on the mathematical convention being employed.