Ooo, I know I know I know <raises hand like Hermione Granger> Mathemagic books by Lynda Colgan are suited for 'on the spectrum' children (& probably not for neurotypical kids, who just want 'real' toys): http://49thshelf.com/Books/M/Mathemagic
Kind-of too late now though....it's Christmas Eve. Anyhow, Merry Christmas!
Darts are quite sharp, hmm.....Maybe he'd like a fish for a pet, like a beta?
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The ones who say “You can’t” and “You won’t” are probably the ones scared that you will. - Unknown