do number four in roman numerals is always be written as IIII instead of IV under every conditions

No, the number four in Roman numerals is almost always written as "IV" in formal and contemporary usage. This is because "IV" follows the standard rules of Roman numerals, where: - **I** represents 1, - **V** represents 5. The number four is formed by subtracting one from five, hence "IV" (5 - 1 = 4). The use of "IIII" to represent the number four is not standard and is considered incorrect in most contexts. It primarily occurs in specific historical contexts, such as some old Roman sundials or clock faces, where it was used for aesthetic or design reasons. Here are some key points to remember: 1. **Standard Usage**: In almost every context, the number four should be written as "IV" in Roman numerals. This includes academic work, historical documents, formal writing, and modern applications. 2. **Exceptions**: The use of "IIII" is a historical anomaly, mainly seen on old sundials, clocks, and some decorative elements. It's not a general rule or standard practice. 3. **Educational Context**: Teachers and educators usually emphasize "IV" for the number four when teaching Roman numerals to ensure clarity and accuracy. 4. **Correctness**: Using "IIII" instead of "IV" for the number four can lead to confusion and is generally considered incorrect in formal settings. In summary, while there are some exceptions, the number four should almost always be written as "IV" in Roman numerals. The primary purpose of Roman numerals is to convey values accurately, and "IV" is the correct representation for the number four based on standard rules.