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Lesson5 |
MULTIPLICATION OF 9
Step1 Prifix 0 before multiplicand
Step2 Take last digit, subtract it from 10 and write it at the extreme
right
Step3 Take second last digit add one and subtract it from last
digit write before step 1 figure
Step4 Now move toward left take third last digit and subtract
it from right neighbour ,write before step 2
figure and repeat
it up to first digit ie 0
123456 x9 = ??
0123456x9 =
Here subtract 6 from 10 ( 10-6=4 ) write 4 at the extreme
right
............4
Take 5 add 1 (5+1 =6) and
subtract it to last digit 6 and write before ..4,6-6=0
............04
Take 4 subtract it from 5 and
write before ....04
5-4 =1
. ..........104
Subtract 3 from 4
and write before ...104
4-3 =1
.........1104
Subtract 2 from 3
and write before ..1104
3-2 =1
........11104
Subtract 1 from 2
and write before..11104
2-1 =1
.......111104
Subtract 0 from 1
and write before.111104
1-0 =1
1111104
1111104 is our required answer
365 x9= ??
0365x9=
10-5 =5
............5
6+1=7 subtract 7 from 5 , take carry
from 6 now 5 become 15 ( 15- 7 =8 )
.......85
Now 6 become 5(adjust carry) subtract 3 from
it
5-3 =2
........285
3-0 =3
3285
3285 is our required answer
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 36 ,.45 ,54. 63 . 72 ,81 and
other multiple of 9
212x36 =( 4x9)x212 = 9x(848)=7632
212x45 = (90/2)x212 = 9x(2120/2)= 9x1060= 9540
43x54=(9x6)x43= 9x(43x6)=9x 258=2322
63x58 =(9x7)x58 = 9x( 7x58) = 9x 406 = 3654
72x23 =(8x9)x23 = 9x(8x23) = 9x184 = 1656
81 x59 =(10-1)9 x59 = (590-59)x9=531x9 = 4779
Practice Test
2589 x9= 5897 x36 = 569x9=
256x45 = 987x63 = 177 x9=
458x54 = 458x9=
2597x72=