As described here:
Nine 9s  
Combining nine 9s with any number of the operators +, , *, /, (, ) , what is the smallest positive integer that cannot be expressed?  
Hints:  







miss:{+/j=!#j@:<j:?j@:&x=j:_ x@:&~0>x}
/ work with all
\t a:*8{x,,?,//x{x y/:'x}/:(+;*;%)}/,9 9.0
/ work with positives
\t b:*8{x,,?,//x{x y/:'x}/:(+;*;%;_abs)}/,,9.0
miss a miss b