Is it OK if I explain it before I write down the next term ?
-1 ___ 3 ___ 11 ___ 23 ___ 39 ___ ( )
The first blank is . . . . . " + 4 = " .
The second blank is . . " + 8 = " .
The third blank is . . . . " + 12 = " .
The fourth blank is . . . " + 16 = " .
So the fifth blank is . . . " + 20 = " and the next number is 59 .
