(53×87+159×21+106×25) is equal to 

What approximate value should come in place of the question mark(?) in the following question?
5223÷36×0.93=?

Simplify the following equations.
1 ÷[{p²/(p+6)}+{6p/(p+6)}]

The sum of a positive integer and its square is 2450. The positive integer is : 

What approximate value should come in place of the question mark (?) in the following question? 
21.9714 × (8.8749 - 4.9393) = ?

What approximate values should come in place of the question mark(?) in the following question?

5.52 – 2.3² + 0.8³ × 0.12 ÷ 0.4⁴ – 3.14 =?

What should come in place of the question mark (?) in the following question?
19.5% of 524 = 50% of ?