What is the value of

C(51, 21) - C(51, 22) + C(51, 23) - C(51, 24) + C(51, 25) - C(51, 26) + C(51, 27) - C(51, 28) + C(51, 29) - C(51, 30) ?

How many odd numbers between 300 and 400 are there in which none of the digits is repeated ?

How many permutations are there of the letters of the word 'TIGER' in which the vowels should not occupy the even positions ?

Let α and β be the roots of the equation x² + px + q = 0. If α³ and β³ are the roots of the equation x² + mx + n = 0, then what is the value of m + n ?