To multiply any two digit number by 11:

For this example we will use 54.

Separate the two digits in you mind (5__4).

Notice the hole between them!

Add the 5 and the 4 together (5+4=9)

Put the resulting 9 in the hole 594. That's it! 11 x 54=594

The only thing tricky to remember is that if the result of the addition is greater than 9, you only put

the "ones" digit in the hole and carry the "tens" digit from the addition. For example 11 x 57 ... 5__7

... 5+7=12 ... put the 2 in the hole and add the 1 from the 12 to the 5 in to get 6 for a result of 627 ... 11

x 57 = 627

Square a 2 Digit Number Ending in 5

For this example we will use 25

Take the "tens" part of the number (the 2 and add 1)=3

Multiply the original "tens" part of the number by the new number (2x3)

Take the result (2x3=6) and put 25 behind it. Result the answer 625.

Try a few more 75 squared ... = 7x8=56 ... put 25 behind it is 5625.

55 squared = 5x6=30 ... put 25 behind it ... is 3025.

To multiply any number by 11 do the following: Working from right to left

1. Write the rightmost digit of the starting number down. 2. Add each pair of digits and write the results down, (carrying digits where necessary right to left). 3. Finally write down the left most digit (adding any final carry if necessary).

It's as simple as that, e.g.

Multiply 712x11

So 712x11=7832

Multiply 8738x11

So 8738x11=96118

Multiplying two numbers between 89 to 100

Multiply 89 x 97

So 89x97=8633.

Multiply 95 x 93

So 95x93=8835

Multiply 97 x 69

So 97x69=6693

Multiply 96 x 88

So 96x88=8448

The same technique works for numbers slightly over 100 except you now have to add

during the Crosswise step. e.g.

Multiply 105 x 107

So 105x107=11235

Multiply 109 x 108

So 109x108=11772

Multiply 123 x 103

So 123x103=12669

Extending the Multiplication Technique

Multiply 1232 x 1003

So 1232x1003=1235696

Multiply 9960 x 9850

So 9960x9850=98106000

Multiply 89684 x 99989

So 89684x99989=8967413476

Multiply 98688 x 99997

So 98688x99997=9868503936