Răspuns:
1558 :a =b rest 58
ab= 1558-58=1500
526:a =c rest 26
ac=526-26=500
1043 :a=d rest 43
ad=1043-43=1000
1500 = 2²·3·5³
500=2²·5³
1000=2³·5³
_______________
cmmdc(1500,500,1000) = 2²·5³ = 4·125 = 500
a=500
1558:500=3 rest 58
526:500=1 rest 26
1043:500=2 rest 43