Comparison

Prime Rush vs 單字雪球

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Prime Rush

Features
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Can you factorize numbers in the blink of an eye? Challenge your brain and reflexes with Prime Rush, the ultimate prime factorization time attack game! This is not just a math drill, it is a high-speed puzzle action game where speed and accuracy are key. Perfect for students studying for exams, adults looking for brain training, and math enthusiasts who love numbers. [HOW TO PLAY] Numbers will appear on the screen. Your goal is to break them down into their prime factors before time runs out! Input the Formula: Use the intuitive keypad to enter factors like "12 -> 2^2x3". It's a Prime!: If the number is already prime, just hit the "It's Prime!" button instantly. Speed Bonus: Answer quickly to extend your time limit. Keep the combo going to achieve a high score! [KEY FEATURES] Time Attack Mode Race against the clock! Start from easy integers and work your way up to massive 3-digit numbers. Global Leaderboards: Compete with players around the world. Your nickname, score, and date are recorded when you beat your personal best. 5 Difficulty Levels: Level 1: Beginners (4 - 50) Level 5: Masters (200 - 999) Can you conquer the hardest difficulty? Practice Mode Need to study without the pressure? Practice at your own pace with no time limits. Ideal for overcoming your weak numbers and understanding the logic behind division. Note: Level 1 is free; Levels 2-5 require a Pro Plan upgrade. Built-in Factorization Calculator Includes a dedicated tool to instantly factorize any number. Use it to check your homework or explore the beauty of prime numbers. Friendly Design Featuring cute "Pochimu" characters to cheer you on. Satisfying sound effects and haptic feedback (customizable in Settings). Share your "New Record" cards directly to social media! [WHY PLAY PRIME RUSH?] Boost Mental Math: Drastically improve your calculation speed for multiplication and division. School Prep: Perfect for middle school and high school algebra preparation. Brain Teaser: A stimulating workout for your frontal cortex. Prevents brain aging with daily logic puzzles. [PRO PLAN] Unlock the full potential of Prime Rush with the Pro Plan to access all Practice Mode levels. Master every number from 4 to 999! Ready to become a Prime Master? Download Prime Rush today and start your mental math workout!

About

單字雪球

This app uses spaced repetition to help you master difficult vocabulary. It offers multiple learning modes, including flashcards and quizzes, and includes a large built-in dictionary with example sentences. Progress is synced via iCloud, and the app is designed for users who already know many words.

Highlights
  • Spaced Repetition System (SRS)
  • 18,000+ word built-in vocabulary
  • Four learning modes: read, quiz, spell, sprint
  • Morphology lookup and reverse Chinese lookup
  • Integrated Cambridge Dictionary
  • iCloud progress synchronization
  • Home and lock screen widgets
Features
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你早就認得很多單字了——真正該花時間的,是那些一直記不牢的幾百個字。 單字雪球用 Anki 式的間隔重複(SRS)排程,把「已經會的」快速分流歸檔,把「還不熟的」在你快要忘記的那一天送回眼前。每天只要清完「今日要讀」,記住的字就像雪球一樣越滾越大。 ■ 18,000 字內建字庫,打開就能背 收錄 18,000 多筆單字,含 KK 音標、中文詞性解釋、英文釋義,以及 79,000 條例句與搭配詞。Level 1~6 對應大考字表分級,想背哪幾級自己勾。完全內建、離線可用,不必匯入字卡,也不用自己建牌組。 ■ 四種學習模式,看心情換 ・讀單字:到期複習自動穿插新字,四鍵評分(再一次/困難/良好/簡單),按鈕上直接顯示下次複習的間隔,按下去之前就知道結果。 ・寫題目:四選一克漏字。答錯的字和誤選的字會自動標記為不熟;題目句子裡的任何一個字都能點開查字義。 ・拼字測驗:看中文解釋和首字母,把英文拼出來。題數、是否納入還沒學過的字、是否影響複習排程,都可以自己決定。 ・清單衝刺:把任意單字丟進自訂清單(考前衝刺、課本第三課、老是搞混的字…),用不計分的循環卡片反覆翻,全部記住才結束。 ■ 為「已經會很多字」的人設計 第一次看到的字按「簡單」就直接歸檔為精通,永遠不再排程、也不佔用每日新字配額;只有測驗答錯或你手動標記不熟時才會被拉回來。每日新字量也會隨著複習積壓自動縮減,不會一次雪崩。 ■ 查得到,才記得住 ・變化型態查找:輸入 studied、running、cities 都能找到原形。 ・中文反查:忘了英文怎麼拼,打中文一樣查得到。 ・內建劍橋辭典:想查更深入時,直接在 app 內開啟 Cambridge Dictionary。 ・單字發音:點一下就聽美式發音。 ・個人筆記:搭配詞、字根、諧音,想怎麼記就怎麼寫,之後複習時會一起出現。 ■ 每天都會想打開 ・連續天數紀錄,加上可自訂時間的每日提醒通知。 ・主畫面與鎖定畫面小工具,一眼看到今天還有幾個字要讀。 ■ 進度存在你自己的 iCloud 學習進度透過 iCloud 私有資料庫自動同步,換手機、重裝 app 都會自動回填。沒有帳號、沒有廣告、沒有訂閱,也不收集你的學習資料。 現在開始滾你的單字雪球。

Screenshots

Prime Rush4 screens
單字雪球4 screens

Verdict

The call

The clearest difference is ads: 單字雪球 at none against Prime Rush's shown. 單字雪球 also leads on update cadence (every 4 days vs every 3 weeks). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Prime Rush sells 1 one-off in-app purchase and 單字雪球 sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Prime Rush ships an update every 3 weeks, 單字雪球 every 4 days. The most recent releases landed on November 9, 2026 and November 6, 2026 respectively.

Scorecard2 real differences · 7 level
Prime Rush versus 單字雪球: the parameters behind the verdict, then further details
ParameterPrime Rush單字雪球
PriceFreeFree
Rating—5.0 (1 ratings) — better
Number of ratings—1 — better
Update frequencyEvery 3 weeksEvery 4 days — better
AdsYesNo — better
In-app purchasesYesYes
Monetization—Free
DevicesiPhoneiPhone, iPad — better
Requires iOS1717.0
Further details — not scored
Size21 MB34 MB
Age rating4+4+
DeveloperAyumu IzumiCHENG-LI CHANG

In-app purchases

1 purchases

Prime Rush

One-time1
  • Pro Plan$1.99
1 purchases

單字雪球

One-time1
  • 記憶線索$2.99

Questions

Is Prime Rush free?
Prime Rush is free to download, with in-app purchases available.
Is 單字雪球 free?
單字雪球 is free to download, with in-app purchases available.
Do Prime Rush or 單字雪球 have ads?
Prime Rush shows ads; 單字雪球 does not.
Which is updated more often, Prime Rush or 單字雪球?
Prime Rush ships an update every 3 weeks, and 單字雪球 every 4 days. Most recently, Prime Rush was updated on November 9, 2026 and 單字雪球 on November 6, 2026.

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