Caps Lock and Num Lock keys are called as ____

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

15, 26, 39, 56, ?, 98

7      8       ?       13       17        22      28

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

35, 38, 46, ?, 85, 120

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

10, 17, 26, 37, 50, ?

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

77, 198, 342, 511, 707, ?

15, 90, 95, ?, 383, 766  

252, 128, 66, 35, 19.5, ?

55      56       52      61       ?       70       34

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

1.5, 3.5, 9.5, 27.5, 81.5, 243.5, ?