Здравствуйте, Нуруллина Светлана Азатовна!
Задачи №1,2,4 в приложении. Задача №3 на множества, очень легкая, как и все, а писанины много.

Приложение:
Задача №1.program q126091_1;uses crt;var a:array[1..50]of integer; n,i,sum:integer;beginclrscr;write(‘n=‘);readln(n);sum:=0;for i:=1 to n do begin write(‘a[‘,i,‘]=‘); readln(a[i]); if a[i]=i then sum:=sum+a[i]; end;writeln;writeln(‘sum=‘,sum);readlnend.Задача №2.program q126091_2;uses crt;var a:array[1..10,1..10]of integer; n,i,j,k,ch,p,max:integer; b:array[1..100]of integer;beginclrscr;write(‘n=‘);readln(n);write(‘k=‘);readln(k);for i:=1 to n do begin for j:=1 to n do begin a[i,j]:=random(20)+1; write(a[i,j]:4); end; writeln; end;writeln;p:=0;for i:=1 to n dofor j:=1 to n doif a[i,j] mod k=0 then begin p:=p+1; b[p]:=a[i,j]; end;max:=b[1];for i:=2 to p doif b[i]>max then begin max:=b[i]; end;writeln(‘Chislo el=‘,p);writeln(‘max=‘,max);readlnend.Задача №4.program q126091_4;uses crt;var s:string; i,k:integer;beginclrscr;write(‘s= ‘);readln(s);k:=0;for i:=length(s) downto 1 doif s[i]=‘:‘then begin k:=k+1; delete(s,i,1); end;writeln(‘snow: ‘,s);writeln(‘kol :=‘,k);readlnend.

Здравствуйте, Нуруллина Светлана Азатовна!
Успеваю только с первой задачкой. Исходник в приложении. Проверен. Работает.

Приложение:
program q126091;uses crt;const Nmax=15;var ch:char; x:array[1..Nmax] of integer; N,i,s:integer;begin clrscr; repeat writeln; write(‘ Input the quality of your numbers : N = ‘); readln(N); if (N>Nmax) or (N<=1) then writeln(‘ Warning !!! Input error : N must be > 1 and <= ‘,Nmax) else begin writeln(‘ Input your numbers : ‘); s:=0; for i:=1 to N do begin write(‘ x[‘,i,‘] = ‘); readln(x[i]); if x[i]=i then s:=s+1; end; if s=0 then writeln(‘ There are not any elements with equal value and number.‘) else writeln(‘ The sum of the elements with equal value and number is : s = ‘,s); end; writeln; write(‘ Again ? (y/n) ---> ‘); ch:=readkey; writeln; until ch=‘n‘;end.