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

1/3 of 785.99 – 11/8 of 1031.99 = ? – 13/4 of 527.98

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

2549.99 - [509.99 - {269.97 - (89.9 - 79.9 + 69.9)}] = ?

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

11.92 + 3(-2.18 × 2.97) - (17.98 ÷ 5.96) = ?

What should come in place of the question mark '?' in the following number series?

17, 52, 158, 477, ? , 4310

What should come in place of the question mark '?' in the following number series?

17, 35, 106, ?, 2126

What should come in place of the question mark '?' in the following number series?

7, 13, ?, 49, 97, 193

What should come in place of the question mark '?' in the following number series?

9, 19, 40, 83, ?, 345, 696

What should come in place of the question mark '?' in the following number series?

46, ?, 284, 345, 378, 391