17/11/18 19:44:36.57 oFg54zrO.net
>>645 Ruby
f = ->a, b, c, d, e, f, g{10000*a + 1000*b + 100*c + d - (1000*e + 10*f + g) == 78037}
[1, 2, 5, 6, 7, 8, 9].permutation{|a| puts "%d%d%d4%d - %d3%d%d == 77777" % a if f[*a]}
#=>87142 - 9365 == 77777
17/11/18 19:44:36.57 oFg54zrO.net
>>645 Ruby
f = ->a, b, c, d, e, f, g{10000*a + 1000*b + 100*c + d - (1000*e + 10*f + g) == 78037}
[1, 2, 5, 6, 7, 8, 9].permutation{|a| puts "%d%d%d4%d - %d3%d%d == 77777" % a if f[*a]}
#=>87142 - 9365 == 77777