perplexus.info :: Numbers : Reduced to single digit

Reduced to single digit (Posted on 2019-09-06)

Suppose that we have two operations that we can perform on an integer:

Multiply it by any positive integer.
Delete the 0's in its decimal representation.

Beginning with any positive integer can we always obtain a single-digit number after a finite number of operations? For example, beginning with 7, we can multiply by 15 to obtain 105, delete the 0 to get 15, multiply by 2 to get 30, then delete the 0 to end with 3.

No Solution Yet Submitted by Danish Ahmed Khan

Rating: 3.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)

re: Possible solution

| Comment 8 of 14 |

(In reply to Possible solution by broll)

I have not completely understood yet, but is this not a problem?

(a corrected example)

(((( 999 * 95) * 99) * 108) * 8) * 5 = 9

( via 9495, 945, 126, 18)

Edited on September 13, 2019, 9:00 am

Posted by Steven Lord on 2019-09-13 01:18:30

Please log in:

Login:
Password:
Remember me:

Sign up! \| Forgot password

Search:

Search body:

Forums (1)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (10)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info