綠蠵龜媽媽帶小綠蠵龜巡沙灘、保護海龜蛋。沙灘是一條數線，每 1 公里一個大刻度，中間有淡淡的小格。孩子把竹竿拖到沙灘上，把沙灘平分成一樣長的幾段（例如 3 公里分給 4 隻），竹竿會對齊小格；每段一樣長以後，再寫出每隻要巡幾公里。第 1 關沙灘比綠蠵龜少（3 ÷ 4 = 3/4），第 2 關沙灘比綠蠵龜多（7 ÷ 3 = 7/3 = 2 又 1/3），第 3 關沙灘只有幾分之幾公里（2/3 ÷ 4 = 2/3 × 1/4 = 2/12）。
適合年級：五年級（約 10～11 歲）。對應 108 課綱（十二年國教）數學單元：五年級「整數相除用分數表示、分數除以整數」。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，也會念出來。
陪玩小提醒：3 公里分給 4 隻，可以把每 1 公里都切成 4 小格，每隻從每公里各拿 1 小格，一共 3 小格，就是 3/4 公里。分數除以 4，就是取它的 1/4，所以等於乘以 1/4。
Mother Green Turtle takes her little ones on beach patrol to guard the eggs. The beach is a number line with a mark at every kilometre and faint small marks in between. Children drag bamboo poles onto the beach to split it into equal stretches (for example 3 km shared by 4 turtles); the poles snap to the small marks. When every stretch is equal, they write how many km each turtle patrols. Level 1 has less beach than turtles (3 ÷ 4 = 3/4), level 2 more (7 ÷ 3 = 7/3 = 2 1/3), and level 3 only a fraction of a km (2/3 ÷ 4 = 2/3 × 1/4 = 2/12).
Suits Grade 5 (about age 10–11) in Taiwan. Taiwan curriculum (12-year basic education) unit: Division as a fraction; dividing a fraction by a whole number (Grade 5). Free with no ads and no sign-up, in Traditional Chinese with zhuyin and in English, read aloud. See the Taiwan elementary maths curriculum map.