Rule 1:  Consonant - Vowel - Consonant (CVC)

• When a one-syllable word is spelled with a consonant-vowel-consonant (CVC) pattern, the last letter should be doubled when adding the endings, -ing or -ed

Rule 2:  Two-Syllable Words

• When the pronunciation of a two-syllable word is stressed on the second syllable, the last letter in the word should be doubled when adding the endings, -ing or -ed.

Rule 3:   Words with a Silent "E"

• When a word ends in a silent "e," remove the "e" before adding "-ing" or
  "-ed."

Rule 4:   Changing "Y" to "I"

• If a words ends in a consonant + the letter y, then change the "y" to "i" when adding the endings, "-ed" or "-es"