Making 100 pencils a day, he made 100 pencils/day * 5 days/week = <<100*5=500>>500 pencils during the week.
With the pencils from the stock, he got 500 pencils + 80 pencils = <<500+80=580>>580 pencils.
Subtracting the ones he sold, he has 580 pencils - 350 pencils = <<580-350=230>>230 pencils.
#### 230