Hi Roelof, Two problems:
1. + is a symbol so compare it to #+ 2. A false case is needed to return the untouched sum, otherwise it truns to nil #(+1 -8) inject: 0 into: [:sum :each | each ~= #+ ifTrue: [sum + each] ifFalse: [sum]] . Hilaire -- Dr. Geo http://drgeo.eu
