The truth is we need to and we do multitask all the time and we cannot n we never multitask in the strictest sense.

Every task includes a lot of tasks. For e.g., I need to think, type and read while writing this comment. Is this one task or three tasks? Even thinking, I need to recall, rationalize and clearly define what I am thinking. So, is thinking one task or multiple tasks.

We cannot perform a single task without multitasking.

However, there is a difference of focus n goal.

How many different goals you are trying to accomplish at the same time?

For instance, you cannot play football on the field and study for exam at the same time. What you can do is recall import points of the subject while looking at the football and waiting for your chance to grab it. It is multitasking in a way, but if you get too absorbed into thoughts related to your exam subject, you might not be able to make the right moves to tackle and get the ball.

Focus is the key. If you truly do something with great focus, you will always be efficient in what you do.

If you are truly focused while learning about your subject, you will not forget anything. Focus is the key. Multitasking will almosy always make you compromise on your dedication towards a task.