a:(b:4)=3 r 2 de unde a=(b:4)*3+2,
c= (a+b:4 ):2 de unde c= [(b:4)*3+2+b:4]:2 =(4*b:4+2):2=(b+2):2,
a) S= (b:4)*3+2 +b + (b+2):2 I*4,
4 S= 3*b +8+4*b+2*(b+2),
4S= 7b+8+2b+4,
4S= 9b+12,
4S= 3 (b+4),
S=3*(b+4) /4,
S= 3*[(b+4)/4] deci S este divizibil cu 3,
b) b-a =2009,
b=2009+a,
b= 2009 +(b:4)*3+2 I*4,
4*b= (2009+2)*4 +3*b,
b= 2011*4 ,
b= 8044,
a = 8044:4*3+2= 2011*3+2=6033+2=6035,
c= (8044+2):2= 8046÷2= 4023,
8044+6035+4023= 18102 divizibil cu 3