Numbers & Multiplications PART-2
Some of you will be having difficulties when multiplication of 9 comes.So here are some tricks with “NINE”.
MULTIPLICATION of TWO NUMBERs between 90-100
The trick is very simple,but again i stress on practice because if you dont practice, the technique won’t come to you when it is required.And knowledge is absolutely worthless if it didnt help in need.
STEP:1 Find the difference of each number with 100,their product will give the last two digits of the final ANSWER.
STEP:2 Now to get the first two digits of the ANSWER you can either subtract the difference of the 2nd number and 100 from the 1st number or the vice versa.This method is called COUNTER DIFFERENCE method.Because both will give you same answer.
Eg.
96*95=?
STEP:1 4* 5=20 (Product of difference with 100)
STEP:2 96-5=95-4=91
ANSWER =9120
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MULTIPLICATION of TWO numbers of which one is full of 9′s.
Eg:
26*99 = (26-1)(100-26)=2574
42*99 = (42-1)(100-42)=4158
I think the 2 examples are self explanatory.
Notes:1
If the number which has only 9′s has more digits than the other then there is a small variation.Here is an example.
Eg:
64*999=?
The number minus ONE will give 63 and 100-64=36 but answer is not 6336.Between 63 and 36 you have to insert as many 9 as the difference between number of digits of both numbers.
64 is two digit number,999 is 3 digit number,So difference is 3-2 =1
Hence add a NINE betweenn 63 and 36 to get the ANSWER,63936.
64*999=63936.
Eg.
76*9999=?
Difference between number of digits is 4-2=2.
Hence 76*9999=(76-1)insert TWO 9(24)=759924
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