After the day but not necessarily after the year
yes you have to because it can be helpful to the reader.
You use commas between items in a list, between the date and the year, and after the greeting in a friendly letter.
Monday 27 April 2009 Is the correct layout. DO NOT use commas. Commas separate elements of a sentence from each other. A date is a collective element. To use the below would be wrong: Say if you use today's date: Monday, 27 April, 2009, or Monday, April 27th, 2009.
Yes, Mexicans use commas in writing to separate items in a list, to mark off introductory words or phrases, and to separate clauses in a sentence. The use of commas in Mexican Spanish follows the same principles as in other varieties of Spanish.
smeell sqiuirly
You can find tips on correct use of commas on grammar.ccc.commnet.edu/grammar/commas.htm
You use commas when your writing a list of things like fruit names. You would not just leave it like this apple orange grapes and pear. You would rather use commas like this apple, orange, grapes and pear.
I do not use commas.
Commas should be used after the first term, stopping at the "and" of the last term, if you don't use oxford commas. For example: There was a dog, cat, bird, fish and monkey. If you do use oxford commas, the comma goes before the and, as well: There was a dog, cat, bird, fish, and monkey. You never use the comma before the last term.
inverted commas
No, not always.
Only when you are listing should you use commas between adjectives. Hope this helped :)