In the large orders, Lisa used 3 large orders * 200g of packing peanuts per large order = <<3*200=600>>600g of packing peanuts.
The rest of the packing peanuts were used in small orders so there was a total of 800g packing peanuts - 600g of packing peanuts used in large orders = <<800-600=200>>200g of packing peanuts used in small orders.
So there must have been 200g of packing peanuts / 50g of packing peanuts per small order = <<200/50=4>>4 small orders.
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