1-1-1 Doubling Rule

The 1-1-1 Doubling Rule states that when adding a vowel suffix to a one-syllable word that has one vowel followed by two consonants, you double the final consonant before adding the suffix.

A 1-1-1 word has one syllable, one vowel, and ends with one consonant that is preceded by one consonant.

Yes, 'run' is a 1-1-1 word.

You double the final consonant to form 'hopping'.

Yes, 'sit' is a 1-1-1 word.

You do nothing; it becomes 'bigger'.

Yes, 'bat' is a 1-1-1 word.

The result is 'tapping'.

Yes, 'red' is a 1-1-1 word.

You double the final consonant to form 'mapping'.