How many meaningful English words can be formed using all the letters of “ERDU”, with each letter used exactly once?

Introduction / Context:
Jumble-based vocabulary questions present a fixed set of letters and ask how many meaningful English words can be formed by using each letter exactly once. The emphasis is on lexical knowledge and systematic enumeration without repetition or omission.

Given Data / Assumptions:

• Letters: E, R, D, U.
• Use each letter once per word.
• Standard English words only; proper nouns and abbreviations are excluded.

Concept / Approach:
List out likely arrangements by anchoring on common consonant-vowel patterns (e.g., RU–, RE–, DR–, DE–). Check each candidate against standard usage, rejecting archaic or highly specialized forms if the test expects everyday words.

Step-by-Step Solution:

Verification / Alternative check:
Cross-verify spelling and meanings: RUDE (impolite); RUED (regretted). Both are commonly recognized, meeting the test’s typical standard for “meaningful” words.

Why Other Options Are Wrong:

• None / One: Under-counts; there are at least two.
• Three: Over-counts; additional everyday words are not available.
• More than three: Greatly over-counts given the constrained letter set.

Common Pitfalls:
Accepting archaic or rare forms (e.g., “dure”) when the test expects common words; duplicating letters or skipping one; overlooking the simple past “rued”.

Final Answer:
Two