{determine if a+b+c=d to a reasonable level of approximatioin}
program u36;
var a,b,c,d,sum:real;
begin
write('first number please? ');
read(a);
write('second number please? ');
read(b);
write('third number please? ');
read(c);
write('sum it should be is ');
read(d);
sum:=a+b+c;
if ( (sum - d) / d > -0.01 ) and ( (sum-d) /d < 0.01 ) then begin
write('the sum of the first three numbers is reasonably close to the fourth');
writeln;
end;