Question regarding order part numbers?

I recently got a job at a car shop in the stocking and warehouse area. Yesterday was my second day on the job, and I have a good grasp of the job. They have me printing out the shipment labels, stocking parts, looking up parts and selling them, delivering parts to other warehouses, and checking stock. The only thing I need to work on is remembering the order numbers for commonly used products. I asked one co-worker that seemed to know a lot of the numbers, and he told me that there are like millions of numbers so it'd be very difficult to know them all quickly. But he knows the air filters and some car part numbers. For those who know the order numbers themselves or happen to just know the order number. What tips do you have to learn them fast?

Question regarding order part numbers?
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