Multiply by 6, 7, 8 & 9

You can use your fingers to multiply by 6, 7, 8 and 9. 

Hold your hands palms up, and point your fingers toward one another.

Assign numbers 6, 7, 8 and 9 to fingers of both hands starting from the bottom to the top.

For example let's multiply 7 x 8.  Touch the finger number 7 on the left hand with the finger number 8 on the right hand.

Add fingers below the touching fingers plus the two touching fingers.  In this case we have one finger on the left hand, two fingers on the right hand and two touching fingers, so our sum is five.

1 + 2 + 2 = 5

These are the tens.

To get ones or units, multiply the number of fingers on the left hand above the touching fingers by the number of fingers on the right hand above the touching fingers.

In this case 3 x 2 = 6, and these are the ones.

Therefore the result is 56.

7 x 8 = 56

***

Now let's try 6 x 6.

There are no fingers bellow the fingers that touch, so there are only two tens, the two touching fingers.
There are four fingers on the left hand and four fingers on the right hand, above the touching fingers, so there are 4 x 4 units, which equals 16.

The result is 20 + 16 = 36,

so 6 x 6 = 36

***

You can practice to find the results for the following multiplications:
 6 x 7, 6 x 8, 6 x 9, 7 x 7, 7 x 9, 8 x 8, 8 x 9

Have Fun!

If you would like a scientific explanation why it works check the book:
Mathemagic! Number Tricks by Lynda Colgan