SQL Function 1

Which of the above are  correct about Single-Row Functions ?

What will be output of the following
SELECT MOD(11,3), MOD(-10,3), MOD(12,2.5), MOD(10,-3) FROM Dual;

What will be output of the following

SELECT ROUND(12345, -2), ROUND(12.345,2),ROUND(12.345,3) FROM Dual;

What will be output of the following

SELECT ASCII('A') Big_A, ASCII('bullraider') SMALL_B FROM dual

What will be output of the following

SELECT INSTR('Mississippi','i',1,1) POS1
, INSTR('Mississippi','i',1,4) POS2
, INSTR('Mississippi','i',-1,3) POS3
FROM Dual;

What will be output of the following

SELECT REPLACE ('SQLQUIZ', 'SQL', 'PLSQL') QUIZ_replace FROM Dual;

What will be output of the following

SELECT SUBSTR('Bull Raider Quiz',-10) from dual;

Which of the following is not an aggregate function ?

COALESCE (expr1, expr2)

What is the meaning of this statement ?

What will be output of the following ?
SELECT  DAYOFWEEK('2013-07-16')   FROM DUAL;