This document provides a cheat sheet for common Excel formulas including SUM, IF, COUNT, MAX, MIN, AVERAGE, VLOOKUP, HLOOKUP, CONCATENATE, IFERROR and tips for using them. It explains how to sum a range of cells instead of just values, always enclose text in double quotes, and how cell references behave when a formula is dragged or copied. It also lists common formula errors like #NAME?, #N/A, #NUM, #DIV/0!, #NULL! and #REF! and how to adjust column width when values are too large.