Five "jobs" of silent final e's are taught. These are explained on pages 56 and 57 of the 5th revised edition of The Writing Road to Reading.
The first "job" of a silent final e (the one used most often) is to let the first vowel say its long sound as in time, make, note, mule, these.
The second "job" of a silent final e is to end words that would otherwise end in v or u. (English words do not end in v or u.)
The third "job" of a silent final e is to change the sound of a c or a g to its second sound as in words like dance or dodge. Rule 3 (page 223) tells us that the letter c followed by e, i, or y always says /s/; g followed by e, i, or y may say /j/.
The fourth "job" of a silent final e is to provide a vowel in a syllable that would not have one without the e. The following syllable patterns require a silent final e be added: ble, cle, dle, fle, gle, kle, ple, sle, tle, zle.
The fifth "job" of a silent final e is called a "no job e" because the spelling is a left-over from middle English. This e serves no other purpose than it is necessary to add it to have correct spelling. Example words would be: are, come, where. It is understood that originally these final e's were pronounced; however, that is no longer the case.
In words that have the vowel-consonant-e pattern, the "job" is always job 1 (time, make, note, mule, these). This "unit" is marked by drawing one line under the vowel, one line under the following consonant, and one line under the e. This marking then shows all the elements of the pattern.