Splicing Arrays in PHP

Задание 1

Given an array:

php<?php
  $arr = [1, 2, 3, 4, 5];
?>

Cut elements from it, so that the array becomes like this:

php<?php
  [1, 4, 5]
?>

Задание 2

Given an array:

php<?php
  $arr = [1, 2, 3, 4, 5];
?>

Get the following slice from this array:

php<?php
  [2, 3, 4]
?>

Задание 3

Given an array:

php<?php
  $arr = [1, 2, 3, 4, 5];
?>

Add new elements to this array:

php<?php
  [1, 2, 3, 'a', 'b', 'c', 4, 5]
?>

Задание 4

Given an array:

php<?php
  $arr = [1, 2, 3, 4, 5];
?>

Add new elements to this array:

php<?php
  [1, 'a', 'b', 2, 3, 4, 'c',  5, 'e']
?>