There can be much confusion about how to pronounce different vowel sounds. One of the easiest ways to understand this is to understand the rule of the silent e. If we consider one-syllable words, this becomes quite clear.

If we add the letter e to the end of the word, we don't add an extra syllable, but rather
the sound of the vowel changes. It becomes a long sound, but the e remains silent.
Notice that the sound made by the long vowel is also the name of the vowel.

The rule is this (where v is a vowel and c is a consonant):

If the root ends in --- c v c e , then the vowel sound is long (its name).

Take note of the differences between these words:
bit & bite
can & cane
cod & code
dam & dame
Dan & Dane
dinner* & diner
fad & fade
fat & fate
fill & file
filling & filing
glob & globe
grip & gripe
her & here
hop & hope
hopping & hoping
mad & made
man & mane
mat & mate
pan & pane
plan & plane
rat & rate
rob & robe
Sam & same
strip & stripe
supper & super
tap & tape
trip & tripe

Even if we remove the silent e to add -ing, the sound of the root is the same to avoid confusion.

If you confuse the names of the letters e and i , think of: I'm mE

*Does dinner mean lunch or supper? There is some disagreement about this, so if you use words lunch and supper, there is never confusion.