D(1,3,4,5) !=0 and D(1,2,4,5) != 9.
D5 cannot be 0 (it would be lowest),
D5 cannot be higher than 2 because d5(3) + d4(6) => d1(9) but d3 is hi
+ghest.
d5 must be 1|2, so d4 must be 2|4, so d1 must be > 3, so d3 must be >
+4. D2 must be 0|1.
Eliminate the impossible
Digit 1 2 3 4 5
-----------------
0 x 0 x x x
1 x 1 x x 1
2 x x x 2 2
3 x x x x x
4 4 x x 4 x
5 5 x 5 x x
6 6 x 6 x x
7 7 x 7 x x
8 8 x 8 x x
9 x x 9 x x
Leaves us these choices.
4 0 5 2 1
5 1 6 4 2
6 7
7 8
8 9
d1+1 = d3 means this further reduces to
40521
50621
60721
70821
80921 *
70842
71842
80942 *
81942 *
Eliminating those * that lack two prime digits leaves five+ six answers? (I think!)
(40521, 50621, 60721, 70821, 70842+, 71842)
+ Corrected. Thanks to crenz.
Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller
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