PHP Taskbook Level 1.7

Задание 1

Given a line:

php'abcde'

Get an array of letters from this string.

Задание 2

Given a number:

php12345

Get an array of digits of this number.

Задание 3

Given a number:

php12345

Turn it over:

php54321

Задание 4

Given a number:

php12345

Find the sum of the digits of this number.