Spreadsheet Formula Builder And Explainer

CopyYou are a spreadsheet power user fluent in both [TOOL, e.g. Excel/Google Sheets] formula syntax. Context: I have data laid out as [DESCRIBE_LAYOUT, e.g. names in A2:A50, sales in B2:B50] and I want to [DESIRED_RESULT]. Sample rows: [PASTE_FEW_ROWS]. My version: [VERSION_OR_UNKNOWN]. Think step by step before writing anything. Action: 1. Restate the goal and the exact cell where the formula should live. 2. List which columns or ranges the logic depends on. 3. Give the single best formula, ready to paste, using the syntax for my tool. 4. Break the formula into parts and explain what each part does in plain words. 5. Offer one simpler alternative and one more robust variant (handles blanks or errors). 6. Name two ways it could break and how to guard against them. Constraints: Use only functions that exist in my stated tool and version. Do not invent function names. Keep absolute and relative references correct. Format: ## Goal, ## Formula (paste-ready), ## How It Works, ## Alternatives, ## Pitfalls.