Reversal

A sequence of 3 or more adjacent characters is reversed.

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A sequence of 3 or more adjacent characters is reversed.

Reversal errors occur when a portion of the string (typically 3-4 characters) is written in reverse order. This can happen when transcribing data from memory or when the eye jumps back while reading. Unlike simple transposition which swaps just two characters, reversal affects a longer sequence.

Substring ABC becomes CBA within the string

123456 → 132456 (123 reversed to 321, shown as 132)
ABCDEF → ACBDEF (BCD reversed)
AB-1234 → AB-3214 (1234 partially reversed)

How to recognize it

Three or more characters appear in reverse order
Length remains the same
All original characters are present

Common mistakes

Confusing with multiple transpositions
Not recognizing partial reversals
Missing the reversal pattern in mixed data

Step-by-step walkthrough

Find the error: Original 'AB-1234' vs Given 'AB-3214'

Compare prefix: 'AB-' = 'AB-'
Compare position 4: '1' vs '3' - mismatch
Compare position 5: '2' = '2'
Compare position 6: '3' vs '1' - mismatch
Compare position 7: '4' = '4'
Pattern identified: '123' was reversed to '321'
This is a 3-character reversal, not simple transposition

Answer: Reversal error: sequence '123' reversed to '321' (positions 4-6)

Practice guidance

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