Rubik's Cube

I have been learning how to solve rubik's cubes since June. I started off simple with the 2x2 cube. Once I could solve it in thirty seconds, I moved onto the 3x3. This surprisingly took a shorter amount of time to learn than the 2x2. That was probably because when I first learned how to solve the 2x2 cube, I was starting from scratch. But when I got the 3x3, I could apply some of the 2x2 tricks. Two days after I got it, I could solve it. Now I can solve it in 1 1/2 minutes. On July 19, my dad's birthday, I got a 4x4. Solving the 4x4 is taking  around twenty minutes right now, but I am sure that I will speed up pretty soon. My mom and dad are also trying to learn the cubes and I am teaching them. The down side of this is that they don't have a lot of free time on their hands. My mom has learnt the 2x2 and 3x3, but along the process of learning  the 3x3, she forgot how to solve the 2x2. She is satisfied with the 3x3 and does not want to move on to the 4x4. My dad is  still learning how to solve the 2x2. He is learning slowly, but steadily. I would love to show you how to solve these, but it will be difficult to explain this process with only words. However, I can display the links to tutorials on how to solve them: 2x2 Cube 3x3 Cube 4x4 Cube