Код: public class A9 { public static void main(String[] args){ double c=0; for (double i=1; i<=97; i+=2){ //System.out.println(i+"/"+(i+2)); c+=i/(i+2); } //System.out.printf("for: "+"%.2f",c); System.out.print("For: "+ c); System.out.println(); double a=1; double d=0; while(a<=97){ //System.out.println(a+"/"+(a+2)); a+=2; d+=a/(a+2); } //System.out.printf("while: "+"%.2f",d); System.out.print("While: "+d); System.out.println(); double e=1; double g=0; do{ //System.out.println(e+"/"+(e+2)); e+=2; g+=e/(e+2); } while (e<=97); //System.out.printf("Do While: "+ "%.2f",g); System.out.print("Do While: "+ g); } } Посему разные ответы? For: 45.124450303050196 While: 45.77131498951884 Do While: 45.77131498951884