如何将分数识别为实体？自定义实体是否需覆盖所有分数变体？

Hey there! Let's work through your questions clearly and practically:

1. 是否需要自定义实体？ #

Definitely yes. Most off-the-shelf entity recognition tools are built to spot standalone numbers, but they don’t natively recognize fractional expressions—whether written in word form like "1 third" or symbol form like "2/5"—as distinct, meaningful entities.

Since your system already catches the trailing numbers (like 9 or twenty), adding a custom fraction entity will let you map these expressions to their actual numerical values (e.g., "1 third" → 1/3, "2/5" → 0.4) and properly handle the "X of Y" calculation logic you’re targeting.

2. 是否需要写出所有需支持的分数变体？ #

You don’t need to list every possible variant upfront, but you should cover the most common categories first, then expand based on real-world usage. Start with these core types:

• Word-based fractions:
  • Simple fractions: "1 third", "two fifths", "a quarter", "half"
  • Mixed fractions: "one and a half", "3 and two thirds"
• Symbol/number-based fractions:
  • Regular fractions: "2/5", "3/4"
  • Mixed fractions with symbols: "1½", "2¾"
• Hyphenated word fractions: "three-quarters", "one-half"

Once you’ve implemented these, test with your target queries (like your examples: "What is 1 third of 9" and "what is 2/5 of twenty") and add edge cases as they come up (e.g., "five-eighths" or decimal equivalents like "0.5" if you need them).

内容的提问来源于stack exchange，提问作者Somk