Rules:

1) If the word ends with a silent e, when adding

the suffix, drop the e

e.g. excite (ends with e)

Drop the 'e' and add the vowel suffix:

excitable

2) If there is a soft 'g' or a soft 'c' before the silent

e, then you can keep the e, before adding 'able' to it.

e.g

manage = manage+able = manageable

notice = notice+able =

3) After a whole root word - add the 'able'

e.g.

reason + able = reasonable

depend + able = dependable

comfort + able = comfortable

understand + able = understandable

enjoy + able = enjoyable

prefer + able = preferable

consider +able = considerable

avoid + able = avoidable