草地下睡著幾隻小刺蝟。孩子翻開草地，數字代表周圍 8 格睡了幾隻；推理出刺蝟在哪裡，就放一顆蘋果幫牠蓋被子，把沒有刺蝟的草地全部翻開就過關。三關從 4×4 草地藏 2 隻、6×6 藏 5 隻，到 8×8 藏 10 隻。
每一盤都經過程式檢查，保證只靠推理就能解開，不用碰運氣；第一下一定安全。叫醒刺蝟就要重來，卡住時可以按「小提示」，會亮出一格一定推得出來的草地並說明原因（會少一顆星）。這款放在奇玩星的「動腦休息區」，不是數學遊戲，不算每日任務和課綱進度；家長可以在家長專區設定要不要先完成每日任務才能玩。免費、無廣告、不用註冊。
陪玩小提醒：卡住時先問孩子「這個數字旁邊還有幾格沒翻開？」答案常常就在那裡。
Little hedgehogs are asleep under the grass. Children uncover grass squares; each number says how many hedgehogs sleep in the 8 squares around it. When they work out where a hedgehog is, they tuck it in with an apple, and they win by uncovering every square without a hedgehog. The three levels grow from 2 hedgehogs on a 4×4 lawn, to 5 on 6×6, to 10 on 8×8.
Every board is checked by the game so it can always be solved by reasoning alone, with no guessing, and the first tap is always safe. Waking a hedgehog means starting again. When stuck, the hint lights up a square that can be worked out and explains why (it costs a star). It lives in WonderPlay’s Brain Break corner: it is not a maths game and does not count towards daily missions or curriculum progress. On the parent page you can ask for daily missions to come first. Free, no ads, no sign-up.