100, 101, 126, 207, 376, 660,

165        155      135      ?      65       15

3, 10, 29, 66, ?

What should come in place of (?) question mark in the given number series.

2, 6, 15, 31, 56, ?

What will come in place of (?) question mark in the given number series.

12, 27, 44, 65, ?, 139

120, 120, ?,  360, 900, 2700

What will come in place of (?) question mark in the given number series.

52, 61, 79, 106, 142, ? 

In each of the following number series, one term is missing. Find the missing term.

7, 15, 31, 63, ?, 255

Find the missing number, in the given number series.

25, 30, 40, 57, ?,  120

What will come in place of the question mark (?) in the following series?

92, 153, 220, ?, 364, 443

(248 + 352)/(34 - 30) = ?