--- type: "App Page" title: "Missing Number Games: Vault Cracker" description: "Crack the vault by finding each missing number in Vault Cracker, a KS2 missing number game. Free one-minute demo, then level up in the Pip app." resource: https://pip11plus.com/ks2-games-arcade/missing-number-game tags: ["ks2-games-arcade", "KS2 SATs", "pip"] timestamp: 2026-10-13T19:42:37Z image: https://pip11plus.com/ks2-games-arcade/img/vault.jpg --- 🕹️ KS2 · Missing numbers and inverse operations # Vault Cracker: Missing Number Game **Vault Cracker is a missing number game where children key in the hidden number on each vault dial, such as ? × 7 = 42.** It suits years four to six and moves from one-step facts to two-step balances. ## Play Vault Cracker ![Vault Cracker game screen: Key in each missing number to spin the vault dials home.](https://pip11plus.com/ks2-games-arcade/img/vault.webp) Missing numbers and inverse operations Years 4 to 6 Difficulty PRO in the app Pip Pro unlocks this game in the app. The one-minute demo here is free, at every level. ![Vault Cracker in the Pip app on a tablet](https://pip11plus.com/ks2-games-arcade/img/vault-640.webp) ### Keep playing in the Pip app Every level of Vault Cracker, and it adapts to your child as they play. [Download Pip on the App Store](https://apps.apple.com/app/pip-11-practice/id6775690698) [Get Pip on Google Play](https://play.google.com/store/apps/details?id=com.pip11plus.app) [Available at Amazon Appstore](https://www.amazon.co.uk/dp/B0HKGJ4HTP) iPhone, iPad, Android and Fire tablets Liked the demo? The full game levels up with your child in Pip. [Download Pip on the App Store](https://apps.apple.com/app/pip-11-practice/id6775690698) [Get Pip on Google Play](https://play.google.com/store/apps/details?id=com.pip11plus.app) [Available at Amazon Appstore](https://www.amazon.co.uk/dp/B0HKGJ4HTP) PRO Pip Pro unlocks this game in the app. The one-minute demo here is free, at every level. ## How to play Vault Cracker 1. Each dial hides a missing number. 2. Tap in the code, then hit the lock. 3. The right code locks the dial, and a wrong one costs 5 seconds. 4. Crack all three vaults before the alarm goes off. ## What your child learns It turns missing number problems KS2 children meet in SATs into a heist, and every dial is an inverse operations game in miniature. These are the KS2 skills it practises. - Missing number problems - Inverse operations - Balancing both sides of an equation - Times tables to 12 × 12 Real examples from the game: ? × 7 = 42**6** 56 ÷ ? = 8**7** 6 × 8 = 12 × ?**4** ? × 4 + 3 = 31**7** ## Levels and difficulty A run is three vaults of four dials inside a 90-second alarm. Vault 1 uses one-step facts up to the 10 times table, vault 2 mixes × and ÷ up to 12, and vault 3 uses two-step balances. The last dial in each vault is always the hardest. Pip moves your child up when they are ready and eases off when they struggle. Each run is short and focused, so it fits before school or homework. ### Every level, in the free Pip app Vault Cracker is part of Pip Pro in the app, with every level and saved progress. [Download Pip on the App Store](https://apps.apple.com/app/pip-11-practice/id6775690698) [Get Pip on Google Play](https://play.google.com/store/apps/details?id=com.pip11plus.app) [Available at Amazon Appstore](https://www.amazon.co.uk/dp/B0HKGJ4HTP) ## Tips for parents and teachers - Teach the inverse first: to find ? in ? × 7 = 42, work out 42 ÷ 7. - For balances like 6 × 8 = 12 × ?, work out the known side (48) before anything else. - Missing number questions appear in KS2 SATs and 11+ maths papers, so this is real exam practice. ## Vault Cracker FAQs **Is Vault Cracker free?** The one-minute demo on this page is free. The full game, with every level, is part of Pip Pro in the app. **Can I play Vault Cracker online?** Yes, for one minute. Press Play above to try the demo in your browser with nothing to install, then carry on in the Pip app. **What age is Vault Cracker for?** Years 4 to 6, within KS2 (ages 7 to 11). The game adapts, so it suits a wide range of children. **Does Vault Cracker work on iPad?** Yes. The demo works in Safari on iPad, and the full game is in the Pip app for iPad, iPhone, Android and Fire tablets. **What are missing number problems in KS2?** They are calculations with one number hidden, such as 56 ÷ ? = 8. Children solve them with the inverse operation. **What are inverse operations?** Operations that undo each other: multiplication and division, addition and subtraction. If 6 × 7 = 42, then 42 ÷ 7 = 6. ## More games like this More maths games in the arcade, plus free practice pages. [Number Smash PRO](https://pip11plus.com/ks2-games-arcade/target-number-game): Tap a colour group whose numbers hit the target, all the way up to Make 24. [Pip Dash FREE](https://pip11plus.com/ks2-games-arcade/times-tables-speed-game): Steer Pip into the lane with the right answer before the fact rushes past. [Pip Match FREE](https://pip11plus.com/ks2-games-arcade/times-tables-memory-game): Flip two cards and match each times table fact with its answer. [Rocket Run PRO](https://pip11plus.com/ks2-games-arcade/division-games): Fly into the asteroid that answers each times table or division fact. - [All maths games for KS2](https://pip11plus.com/ks2-games-arcade/maths-games) - [The KS2 Games Arcade](https://pip11plus.com/ks2-games-arcade) - [11+ maths questions](https://pip11plus.com/maths-questions) - [KS2 SATs practice](https://pip11plus.com/ks2-sats) ## Bookmark the arcade - On a computer: press Ctrl and D, or Cmd and D on a Mac. - On iPad or iPhone: tap Share, then Add to Home Screen. - On Android: tap the menu, then Add to Home screen. ## More KS2 games [Vocab Fishing FREE](https://pip11plus.com/ks2-games-arcade/11-plus-vocabulary-games): Read the clue, then hook the fish carrying the right word before the shark does. [Word Orchard FREE](https://pip11plus.com/ks2-games-arcade/ks2-vocabulary-games): Tap the apple with the right word to grow your orchard. [Word Tower FREE](https://pip11plus.com/ks2-games-arcade/synonyms-game): Stack synonyms in order of strength before the tower wobbles over. [Homophone Heist PRO](https://pip11plus.com/ks2-games-arcade/homophones-game): Sneak to each laser gate and pick the homophone that fits the gap. ## Give your child the Pip advantage Vault Cracker plus 18 more games and adaptive practice, five calm minutes a day. [Download Pip on the App Store](https://apps.apple.com/app/pip-11-practice/id6775690698) [Get Pip on Google Play](https://play.google.com/store/apps/details?id=com.pip11plus.app) [Available at Amazon Appstore](https://www.amazon.co.uk/dp/B0HKGJ4HTP) [All KS2 games](https://pip11plus.com/ks2-games-arcade) Free · no sign-up