1 x 1 = 1
11 x 11 = 121
111 x 111 = 12321
1111 x 1111 = 1234321
11111 x 11111 = 123454321
111111 x 111111 = 12345654321
1111111 x 1111111 = 1234567654321
11111111 x 11111111 = 123456787654321
111111111 x 111111111=123456789 87654321
2006-09-29 00:11:24 · 10 answers · asked by iamgood 2 in Science & Mathematics ➔ Mathematics
you have too much spare time.
2006-09-29 00:21:46 · answer #1 · answered by steve 4 · 1⤊ 0⤋
A method to multiply 11 mentally is to break it into 10+1 to multiply so we end up adding similar numbers. e.g. 11 x 986 = (10 + 1) x 986 = 9860 + 986
Here, the other number is a sequence of 1's, so we are adding a sequence of 1's with different number of zeros appended behind. E.g. 1111 x 1111 = 1111000 + 111100 + 11110 + 1111, written vertically:
1111000
0111100
0011110
0001111
Thus, there is 1 1's on the extreme columns, an additional 1's each column inward.
Some of it will be the digit representing the number of 1's in each column at the corresponding digit position of the number.
Similarly true for the rest where the number of 1's is less than 10.
2006-10-02 21:25:52 · answer #2 · answered by back2nature 4 · 0⤊ 0⤋
this is called number theory and modern algebra
2006-09-29 04:21:43 · answer #3 · answered by michaell 6 · 0⤊ 0⤋
not bad but that's a common one. how many do u know?
2006-09-29 00:24:20 · answer #4 · answered by Lila 3 · 0⤊ 0⤋
this is crap...Study vedic maths
2006-09-29 00:17:33 · answer #5 · answered by robin 3 · 0⤊ 0⤋
Hey! NEETO!!!!!!!! WOOOOOOO!!!!!!!! math
2006-09-29 00:21:37 · answer #6 · answered by ITS ME 3 · 0⤊ 0⤋
its clever ill give you that!!!
2006-09-29 00:19:09 · answer #7 · answered by Anonymous · 0⤊ 0⤋
oh sure, thts awesome!!!
2006-09-29 00:15:44 · answer #8 · answered by Anonymous · 0⤊ 0⤋
I like it....
Please post more...........
2006-09-29 00:15:12 · answer #9 · answered by Christa 2 · 0⤊ 0⤋
great.....cool...
ya..post more..
2006-09-29 00:19:19 · answer #10 · answered by P.Y.T. 3 · 0⤊ 0⤋