Mental Math play online

Think for a moment about some mathematical calculations such as:

78 * 25
997 * 998
579 * 11
32 * 75
47 * 89
77 * 93
24 * 99
78 * 78
387 * 387

and so on. What if I told You that with appropriate knowledge and some practice You can do each and every of these tasks in Your head literally in matter of seconds? Don't believe me? Well, it's true. Not only that but You could also often do it faster than Your friend using a calculator. Sounds impossible? On the contrary, it is very easy with the right tools for the job. Those tools are called "mental mathematics" which is the main subject of this application...