determinati numerele abcd stiind ca abcd5-abcd=18158. Dau coroana

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

abcd5-abcd=18158
4abcd=18158
abcd=18158:4
abcd=4539.5