河狸技師阿木要修好一台台機器人，需要的螺絲數是一道直式乘法，例如 248 × 36。孩子在「直式乘法機」的齒輪格子裡填數字：先算 248 × 6 填第一列，再算 248 × 3，把第二列的托盤往左拖一格（因為其實是乘 30，後面補 0），最後把兩列加起來。每填好一列，機器人就裝回一個部位。答錯時會指出是哪一格，並寫出那一格的算法和進位。
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「多位數的乘法和除法直式」（三位數乘以二位數）。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。需要先熟悉九九乘法，所以要先玩過一款乘法表遊戲才會開放。免費、無廣告、不用註冊，題目有注音，也會念出算式。
陪玩小提醒：直式乘法最常錯在第二列沒有往左移一格，和忘了加上進位。可以問孩子「乘十位的 3，其實是乘多少？」，算完再用估算（250 × 40）檢查答案合不合理。
Moo the beaver mechanic needs a number of screws for each robot, and the number is a long multiplication such as 248 × 36. Children fill the gear cells of the multiplying machine: first 248 × 6 in row 1, then 248 × 3 on a tray they drag one column left (it is really × 30, so a 0 fills the ones), then add the two rows. Each finished row puts a part back on the robot, and a mistake points to the cell with its working and carry.
Suits Grade 4 (about age 9–10) in Taiwan. Taiwan curriculum (12-year basic education) unit: Long multiplication and long division with bigger numbers (Grade 4). It opens after one times-table game has been played. Free with no ads and no sign-up, in Traditional Chinese with zhuyin and in English, with sums read aloud. See the Taiwan elementary maths curriculum map.