If M denotes ‘−’, N denotes ‘÷’, O denotes ‘×’ and P denotes ‘+’, then what will come in place of ‘?’ in the following equation?
(38 O 13) N 19 M 27 P (38 O 3) P 43 M 68 = ?

Which of the following interchanges of numbers and mathematical signs would make the given equation correct?
 729 × 81 ÷ 20 + 16 − 6 = 50

If A denotes ‘+’, B d enotes ‘×’, C denotes ‘−’ and D denotes ‘÷’, then what will come in place of ‘?’ in the following equation?
 41 C 29 A (38 B 3) D 19 A 61 C 17 = ?

Direction: Some equations have been solved on the basis of certain system. Find the correct answer for the unsolved equation on that basis.

If 1 + 4 = 9, 2 + 8 = 18, 3 + 6 = 15 then 7 + 8 =?

After interchanging the two numbers 3 and 6, what will be the value of the given expression?

12 × 3 ÷ 6 + 8 – 2

If A denotes ‘+’, B denotes ‘×’, C denotes ‘−’ and D denotes ‘÷’, then what will come in place of ‘?’ in the following equation?
 (13 B 9) D 3 A (14 D 7) B 6 C 21 A (32 B 2) = ? 

After interchanging which two signs will the value of the given expression be ‘356’?

133 + 49 – 16 ÷ 2 × 34

If  ‘+’  means ‘÷’,   ‘ ̶ ’  means  ‘+’,   ‘×’ means  ‘ ̶ ’  and   ‘÷’  means  ‘×’,   what will be the value of the following expression?
 [{(38 × 23) - (4 ÷ 3)} + (6 - 3)] ÷ 2