8 x 2 = <<8*2=16>>16 are blue pens.
16 + 10 = <<16+10=26>>26 are black pens.
8 - 2 = <<8-2=6>>6 are red pens.
Therefore, there are 16 + 26 + 6 = <<16+26+6=48>>48 pens in all in Sam's collection.
#### 48