Multiplication

INSTANT MULTIPLICATION 

Multiplication

Let’s begin with one of my favorite feats of mental math—how to multiply, in your head, any two-digit number by eleven. It’s very easy once you know the secret. Consider the problem:

32  x 11 

To solve this problem, simply add the digits, 

3 + 2 = 5 , put the 5 between the 3 and the 2, and there is your answer:

352

What could be easier? Now you try:

53 x 11

Since 5 + 3 = 8, your answer is simply

583

One more. Without looking at the answer or writing any-thing down, what is

81 x 11 ?

Did you get 891? Congratulations! Now before you get too excited, 

I have shown you only half of what you need to know. Suppose the problem is

85 x 11

Although 8 + 5 = 1 3 , the answer is NOT 8135! As before, 

the 3 goes in between the numbers, but the 1 needs to be added to the 8 to get the correct answer:

935

Think of the problem this way:

                                                                                                          1

                                                                                                          835

                                                                                                          935