Mission: Master Inverse Operations & Estimation
Operation Outpost places Year 4 recruits in charge of a high-tech sensor grid. Your mission? To validate incoming data using two critical mathematical verification techniques: Inverse Operations and Estimation.
1. Inverse Operations
Inverse operations are "opposite" operations that undo each other. They are the best way to double-check your calculating.
- Addition ↔ Subtraction: If calculated that
1200 + 1300 = 2500, check it by doing2500 - 1200 = 1300. - Multiplication ↔ Division: These are also inverses (covered in future training!).
2. Estimation
Estimation helps you spot obvious errors quickly by rounding numbers to make them easier to calculate mentally.
- Rounding: Round
3,912 + 2,105to4,000 + 2,000. - Approximate: The answer should be roughly
6,000. If your calculator says 60,000, you know it's a glitch!
Curriculum Link: Year 4 Number
This game directly addresses the National Curriculum aim: "Estimate and use inverse operations to check answers to a calculation."
