Default to zero on missing discount (VLOOKUP + IFERROR)
You are processing store checkouts. Members get a discount based on their VIP tier in columns A–B (Bronze 5%, Silver 10%, Gold 15%, Platinum 20%). Non-VIP customers have standard tiers like 'Regular' or 'None' that are NOT in the VIP table, causing a naked VLOOKUP to fail with #N/A. Fill the Discount cells E2:E5 using VLOOKUP wrapped in IFERROR (or IFNA) so missing tiers safely default to 0.
Your solution should use cell references so it updates automatically when Test Case input values change.
Notes
When lookup outputs feed directly into arithmetic (e.g. Total * (1 - Discount)), returning a text like 'Not found' or letting #N/A bubble up will break the whole formula. Wrapping VLOOKUP in IFERROR with a 0 fallback keeps calculations running cleanly.
Function guide
FAQ
Why return 0 instead of "No Discount"?
When the discount cell is later multiplied by the order amount (e.g. Price * (1 - Discount)), text causes a #VALUE! error. A numeric 0 allows subsequent math formulas to compute without errors.
Should I use IFERROR or IFNA for VLOOKUP?
IFNA is generally preferred for lookups because it only suppresses #N/A (lookup miss). IFERROR will also silence #REF! (deleted column), which could mask critical worksheet bugs.