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Lesson13 |
Division by 9
Division by 9 is also very easy and you can do it very fast mentally
The first figure of 23 is 2, and
this is the answer.
The remainder is just 2 and 3 added up!
The first figure 4 is the answer
and 4 + 3 = 7 is the remainder - could it be easier?
The answer consists of 1,4
and 7.
1 is just the first figure of 133.
4 is the total of the first two figures 1+ 3 = 4,
and 7 is the total of all three figures 1+ 3 + 3 = 7.
See one more example
1232 / 9 = 136 remainder 8
Actually a remainder of 9 or more is not usually
permitted because we are trying to find how
many 9's there are in 842.
Since the remainder, 14 has one more 9 with 5
left over the final answer will be 93 remainder 5
See one more example
Answer in decimal
Take above example 123456 / 9 = 13717 remainder 3
It is very very easy put decimal after 13717 write remainder 3 and repeat it again and again .
13717 .3333333333333.. It is our required answer .
With the help of this concept we can solve
some other problems
Take few examples
1234/81 = ????
It is just 1234 we divide 1234 by 9
two times and get required answer
9x9
= 136 1 remainder 1
= 137.1111111 =1 41.23456
=15.23456
9
9
362/63 =?????? 362
= 31 0 remainder 2
= 4 0.222222 = 5.7460
9x7
7
7
489/45 = ????? Apply
little presence of mind here ,Multiply 489 and 45 to 2
489x2 = 978 = 108remainder
6 = 108.66666 = 10.866666
45x2 90
90
10