Răspuns :
D-R=55 ; D=55+R ( D= dempartit; R=rest ; I= impartitor)
I=5
D=C x I+ R=55+R
5C=55; C=11( RESTUL POATE FI 1,2,3 SAU4)
x:5=cat, rest x=5×cat+ rest 5×cat=x-r (x-r=55)
x-r=55 c=? 5×cat=55
cat=55:5
cat=11
x-r=55 c=? 5×cat=55
cat=55:5
cat=11