Days, ordinal numbers and must

Ordinal numbers show order: one → first (1st), two → second (2nd), three → third (3rd), four → fourth (4th), five → fifth, six → sixth, seven → seventh, eight → eighth, nine → ninth, ten → tenth, eleven → eleventh, twelve → twelfth. We use the before them. Days of the week: “Thursday is the fourth day of the week.” “Saturday is the sixth day.” Question: “What’s the sixth day of the week?” — “Saturday.” For calendar dates: “the 3rd” (the third). Watch the spelling of five → fifth, eight → eighth, nine → ninth, twelve → twelfth.