Răspuns :
abcd5 - abcd = 18158
10000a+1000b+100c+10d+5-1000a-100b-10c-d = 18158
9000a+900b+90c+9d +5 = 18158
9(1000a+100b+10c+d) = 18158-5=18153
1000a+100b+10c+d = 18153:9
1000a+100b+10c+d = 2017
Numarul abcd barat este atunci 2017
10000a+1000b+100c+10d+5-1000a-100b-10c-d = 18158
9000a+900b+90c+9d +5 = 18158
9(1000a+100b+10c+d) = 18158-5=18153
1000a+100b+10c+d = 18153:9
1000a+100b+10c+d = 2017
Numarul abcd barat este atunci 2017