1)
var a,i :integer;
begin
write('a = '); readln(a);
for i:=10 to 99 do
if (i mod 10 = a) or (i div 10 =a) then write(i,' ');
end.
2)
var i :integer;
begin
for i:=10 to 99 do
if (i mod 10 + i div 10) mod 5 =0 then write(i,' ');
end.
3)
var a,b,i,sum:integer;
begin
write('a = ');readln(a);
write('b = ');readln(b);
sum:=0;
for i:=a to b do sum:=sum+i;
writeln('Ср. арифм. = ', sum/(b-a+1));
end.