12 beginner→advanced exercises: equals sign, operators, order of operations, relative reference, $ locking, mixed reference, range, string concatenation, divide-by-zero trap, structured reference, number formatting, formula auditing. AUTO-graded. · 12 lessons · progress saved right on your device.
Source: Sơn Sunny — original formulas, auto-graded · © Sơn Sunny — own course, own verifier