孩子把分數電池包拖到小車上充電：一顆電池充滿了，電會流進下一顆，親眼看到 7/5 = 1 又 2/5；最後開一段路，電一格一格用掉，算出還剩多少。
適合年級：四年級（約 9～10 歲）。對應 108 課綱（十二年國教）數學單元：四年級「同分母分數、假分數和帶分數」。各版本教科書的單元順序不同，完整對照請看國小數學課綱對照表。免費、無廣告、不用註冊，手機、平板、電腦打開就能玩，題目有注音，也會念出算式。
陪玩小提醒：分母一樣時，加減只要算格子數；每滿分母那麼多格就是 1，這就是假分數換成帶分數。
Children drag fraction battery packs onto a little car. When one battery is full the charge flows into the next, so they see that 7/5 = 1 and 2/5. Then they drive along a road, using one part of charge per stretch, and work out what is left.
Suits Grade 4 (about age 9–10) in Taiwan. Taiwan curriculum (12-year basic education) unit: Like fractions, improper fractions and mixed numbers (Grade 4). Free with no ads and no sign-up, in Traditional Chinese with zhuyin and in English, with questions read aloud. See the Taiwan elementary maths curriculum map.