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Multiplying a number by 11
To multiply any figure number by 11 we just put
the total of the two figures between the 2 figures.
32X11
Here first we write 2 of 32 extreme right ,now add up 3+2 =5
,put 5 before 2 and write 3 extreme left .Required answer is 352
322x11
Write extreme left 2of 322 and add up 2&2 of 322 ,
2+2=4 ,write 4 before 2 Now our partial answer
is ...........42 .Again add up 3&2 of 322 .3+2 =5 write
before ..42 .Now our partial answer becomes ..542 .Put
3 before 5 . Now our required answer is 3542
- 77 x 11 = 847
This involves a carry figure because 7 + 7 = 14
we get 77 x 11 = 7147 = 847
Multiplication of 22 ,33 ,44 ,55, 66
, 77 ,88
I think all of you understand this concept . It is a very useful tool
,with the help of this tool
now we learn multiplication of 22 ,33 .44 ,55. 66 . 77 ,88
22x45 =( 2x11)x45 = 11x(2x45)=11x90= 990
33x66 = (3x11)x66 = 11x(3x66)= 11x198= 2178
44x356=(4x11)x356= 11x(4x356)=11x 14 24=1 5664
55x58 =(5x11)x28 = 11x( 5x28) = 11x 140 = 1540
66x23 =(6x11)x23 = 11x(6x23) = 11x138 =
1518
Same way 77 =7x11 and 88=8x11 |
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Multiplication of 11 is great time
saver How ???
You can do calculations in Mensuration very fast by
this tool
As you know value of pi is 22/7 .You can break it as 2x11/7
Ex Find the area of circle of radious of 14 cm
(22/7)x14x14=11x2x2x14=11x56=616square cm
All calculation mentally, no rough work ,
a great time save.
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