Examples:
dose+age = dosage
damage+ed = damaged
fine+est = finest
gape+ing = gaping
fame+ous = famous
ice+y = icy

Exceptions:

• Words ending in -ce and -ge usually keep their 'e' to clarify the pronunciation of a preceding consonantal sound.
  Examples: replaceable, changeable
• The final e is also retained for words ending in -ee.
  Examples: agreeable, foreseeable
• The words 'acreage' and 'mileage' retain their 'e'
• The silent 'e' is retained if it is required for clarifying the pronounciation of the word. Examples: dyeing, advantageous

Examples:
uncontrol+able = uncontrollable
drop+ed = dropped

Exception: Instead of doubling a final consonant 'c', it becomes ck before the addition of a suffix.
Example: frolic+ing = frolicking