top button
Flag Notify
    Connect to us
      Site Registration

Site Registration

Start with a two-digit number, reverse digits to make a new number then subtract the smaller from the larger number...

+1 vote
175 views

Start with a two-digit number, reverse the digits to make a new number then subtract the smaller from the larger number. Repeat this process until you reach a single digit. Start with other numbers. What do you notice, answer with the explanation why is it happening.

posted Nov 28, 2017 by anonymous

Share this puzzle
Facebook Share Button Twitter Share Button LinkedIn Share Button

1 Answer

+1 vote
 
Best answer

Let any 2 digit number be (10×a + b) then on reversing the digit's places we get (10×b + a). Now subtracting the 2 gets us
(9×a - 9×b) = 9(a-b). Therefore for any 2 digit number the following steps always yields a number which is either 9 or it's multiples and when continued gives 9 as the answer in one of its steps.

answer Nov 28, 2017 by Tejas Naik



Similar Puzzles
0 votes
Write 3-digit number whose 1st digit differs from last by 1. Reverse the digits and subtract smaller from larger one.

Write any three-digit number whose first digit differs from its last by 1. For instance 627 or 506. Reverse the digits then subtract the smaller from the larger number. Do this with several numbers. What do you notice? Does this always happen?

0 votes
When a two digit number is multiplied by sum of its digits, the product is 715 but when the reverse of a two digit......

When a two digit number is multiplied by sum of its digits, the product is 715 but when the reverse of a two digit number is multiplied by sum of its digits the product obtained is 99 less.
What is the sum of the digits of a number?

0 votes
In this teaser, you are to start with the letter 'I' and then each time add a letter and shuffle it to make a new word.

In this teaser, you are to start with the letter 'I' and then each time add a letter and shuffle it to make a new word.
You need to continue this process until you reach the word 'CAMPING".
Not including 'I', you must do this in six (6) turns.
Good Luck.
I
to
CAMPING

+1 vote
In this teaser, you are to start with the letter 'U', and then each time add a letter and shuffle it to make a new word.

In this teaser, you are to start with the letter 'U', and then each time add a letter and shuffle it to make a new word. You need to continue this process until you reach the word 'PRODUCE'.

Not including 'U', you must do this in six (6) turns.

Good luck.

U
_ _
_ _ _
_ _ _ _
_ _ _ _ _
_ _ _ _ _ _
P R O D U C E
...