If ‘+’ means ‘-‘, ‘-‘ means ‘x’, ‘x’ means ‘÷’ and ‘÷’ means ‘+’, then what will be the value of the  following expression?
27 – 2 + 24 × 8 ÷ 4

Which two signs need to be interchanged to make the following equation correct?
45 – 9 ÷ 3 +5 ×6 =32

How many numbers are there between 1 and 100 which start or end at 2? 

Two years ago, Roshni's age was 3 times her son's age, and 2 years later, 2 times her age would be 5 times her son's age. Find the current age of Roshni.

A father was twelve times as old as his son twenty years ago. Now he is twice as old as his son. What are the present ages of the son and father?

The total age of a mother and her son is 60 years. The difference between their ages is 30 years. Find out the age of the mother.

A father's age was 8 times his son's age 4 years ago. Presently the father's age is 4 times that of his son. Find the present age of the son?

If 6 * 9 – 4 = 58 and 3 * 9 – 7 = 34, then in the expression A * 4 – 9 = 91, what is the value of 'A'?