Averages · built from real SSC papers

Averages, the Fast Way

Turn every average into a total, lean on the (first+last)/2 shortcut, and shift the mean with one deviation step instead of redoing the whole sum. Pick any topic to start — nothing is locked.

6 topics · every exam question type

🧮1. Average & Total BasicsAverage × count = total; missing numbers; combining groups1 type 🔢2. Series & AP ShortcutsConsecutive / even / odd / multiples; (first+last)/2 = middle1 type 🔗3. a, b, c RelationshipsOverlapping pair-averages and multi-variable equations2 types 🔄4. Join, Leave & ReplaceOne person in/out, replacements, and groups merging2 types ⚖️5. Weighted & Special SetsDifferent group sizes; primes and special number sets2 types 🎂6. Ages & Error CorrectionAges over time; misread / wrongly-entered values2 types