Math Is Fun Forum

G_Einstein

Member

Registered: 2008-08-30

Posts: 124

Multiplying with fingers!!!!!!

You can multiply numbers with 9 using your fingers.
Example.
9X3=27
Now look your 10 fingers,and when you multiply 9 by a number,the number wich is used to multiply 9 is your finger (starting from the left to the right) that you should "hide",so 9X3=27,and if you "hide" your third finger you will se that in the beginning you have 2 finers,and after the "hiden" finer you'll have seven fingers,so it makes 27!!!!!!!

Another example:
9X7=63
"Hide" your 7-th finger(the seventh beginning from the left to the right) and you'll have,6 fingers in the beginning and 3 fingers at the end!!!!!!!!!!

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luca-deltodesco

Member

Registered: 2006-05-05

Posts: 1,470

Re: Multiplying with fingers!!!!!!

hah, never thought of that ^^

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The End Of All Things To Come.

Alyssa_96

Member

Registered: 2008-08-08

Posts: 4

Re: Multiplying with fingers!!!!!!

this is a great tip.

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"If the heart is the strongest muscle, than why does it break so easily?"

EddieRingle

Member

Registered: 2008-09-03

Posts: 2

Re: Multiplying with fingers!!!!!!

My mom showed me that when I first started multiplication, it helped a lot.

mathsyperson

Moderator

Registered: 2005-06-22

Posts: 4,900

Re: Multiplying with fingers!!!!!!

I recently found a way of using fingers to multiply two numbers between 6 and 10.

Hold your palms out with your fingers pointing at each other and the thumbs pointing up.
Number them so that your little finger is 6, your ring finger is 7, and so on up to your thumb being 10.

Now close the fingers corresponding to the two numbers you want to multiply. So, 8x7 would mean closing the middle finger of your left hand and the ring finger of your right.

Count up all the fingers below and including the closed ones. In the 8x7 example, this is 5.
Multiply this number by 10.

Then multiply together the amounts of fingers above the closed one in each hand.
Here, there are 3 fingers above the closed one in the left hand, and 2 in the right. Multiplying these gives 6. Add this to the previous number to get the answer - 50 + 6 = 56 = 8x7.

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It wanted to be normal.