Re: Hint 2 Solution order
Larry Barrett
F could be any of the digits 0, 1. 2. ... 9.
To find out which are possible, multiply each by the numbers 1, 2, ... 6. Examine the 'ones' place in the answers. There can not be any repeats in the 'ones' place because of the way the problem is stated. So, for instance, F can not be 5 because 5 multiplied by 1, 2, .. 6 is 5, 10, 15, 20, 25, 30 and we see that the digit 5 is repeated several times in the 'ones' column. Similarly, 0, 2, 4, 5, 6, 8 can all be eliminated for F. But F could be 1, 3, 7, or 9. We already know that A is 1, so F could still be 3, 7, 9.
We do know that the digit 1 must appear in the 'ones' place in the F column because it also appears in the A column (1x1=1 and there would be no carry from column B). By examining 3 and 9 each multiplied by 1, 2, ...6 we can see that 1 does not appear in the 'ones' column. F must therefore be 7. And when examining the 'ones' column for F, we can see that the remaining numbers for B, C, D, and E must be 4, 8, 5, 2, in some order.
Now, cheating a bit and making use of Sam's hint, we can guess that B=4 and C=2. It remains to try 8 and 5 for D and E.
First guess is D=8 and E=5.
With my handy Sharp calculator, entering 142857 and saving it in memory, then multiplying that by 1, 2, ... 6 I see those same digits repeated in the answer, in different order.
So ABCDEF is 142857.