Practice on If-Else Conditions in PHP

The variable $month contains some number from the interval 1 to 12. Determine which season this month falls into (winter, summer, spring, autumn).

A string is given, consisting of characters, for example, 'abcde'. Check that the first character of this string is the letter 'a'.

A number is given, for example, 12345. Check, that the first digit of this number is 1, 2 or 3.

A three-digit number is given. Find the sum of the digits of this number.

A number of 6 digits is given. Check, that the sum of the first three digits equals the sum of the second three digits.