(0.3\overline18) (x = 0.3181818\ldots) Multiply by 10: (10x = 3.181818\ldots) (now pure repeating: (3.\overline18)) (1000x = 318.181818\ldots) (since (10x \times 100 = 1000x)) Wait — better method: Let (x = 0.3\overline18) Multiply by 10: (10x = 3.\overline18) (pure repeating) Now (10x = 3 + 0.\overline18) (0.\overline18 = \frac1899 = \frac211) So (10x = 3 + \frac211 = \frac33+211 = \frac3511) Thus (x = \frac35110 = \frac722)

(0.\overlineabc\ldots = \frac\textrepeating block10^n - 1) where (n) = number of digits in the block.

Both terminating and repeating decimals have a geratrix fraction. Irrational decimals (e.g., (0.1010010001\ldots)) do not. Case 1: Terminating Decimal Write the decimal as a fraction with a power of 10 in the denominator, then simplify.

(0.\overline72) (x = 0.727272\ldots) (100x = 72.727272\ldots) Subtract: (100x - x = 72 \Rightarrow 99x = 72 \Rightarrow x = \frac7299 = \frac811) Case 3: Mixed Repeating Decimal Let (x) be the decimal. Multiply by a power of 10 to move the decimal point to just before the repeating block, and by another power to include the whole repeating part. Subtract.

The decimal (0.333\ldots) (or (0.\overline3)) is generated by the fraction (\frac13). Therefore, (\frac13) is the geratrix fraction of (0.\overline3). 2. Types of Decimals | Type | Description | Example | |------|-------------|---------| | Terminating decimal | Ends after finite digits | (0.25 = \frac14) | | Pure repeating decimal | All digits after the decimal point repeat | (0.\overline142857 = \frac17) | | Mixed repeating decimal | Some non-repeating digits followed by a repeating block | (0.1\overline6 = \frac16) |