The magic of 9

The magic of 9

1. If we multiply any number by 9 and add the digits of the answer we get till we get a single digit, the single digit will always be 9.

For example

853 x 9 = 7677 , 7 + 6 + 7 + 7 = 27 , 2 + 7 = 9

456987 x 9 = 4112883 , 4 + 1 + 1 + 2 + 8 + 8 + 3 = 27 , 2 + 7 = 9

178342342 x 9 = 1605081078, 1 + 6 + 0 + 5 + 0 + 8 + 1 + 0 + 7 + 8 = 36, 3+ 6 = 9

2. Multiply any number by 9, 99, 999

To multiply any number by 9, 99, 999 etc put as many zeroes are there are 9's in the multiplier and from the result subtract the number itself.

For example to find the value of 345 x 99

Step 1 : 99 has 2 digits hence put 2 zeroes after 34500

Step 2 : Subtract 345 from the above number that is 34500 - 345

Step 3: Solve step 2 to find the answer

Hence 345 x 99 = 34500 - 345 = 34155

98934 x 9999 = 989340000 - 98934 = 989241066

Explanation:

999 x 582 = (1000-1) x 582

= 582000 – 582

= 581418

3. If you take any multiple of 9 and reverse the digits the answer will also be a multiple of 9.

Example : 45 is a multiple of 9, 54 is also a multiple of 9.

2115 is a multiple of 9. 5112 is also a multiple of 9.

From

10on10 Team