變色龍魔術師把算式寫在魔術板上。第 1 關孩子要點出「該先算的那一步」：先乘除後加減，一樣的時候從左邊算起，點對了再算出那一步的答案，算式一步步變短；第 2 關括號裡的先算，接著要自己點兩個數字放上括號，讓算式變出魔術師指定的數；第 3 關把兩步驟應用題（含連除）用數字和符號卡拼成一條併式，再用算式寫出火柴棒、三角形和長桌座位的規律，算出第幾個要多少。
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「併式和四則混合計算」「兩步驟應用題」「用文字表示公式、數量的規律」。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。要先玩過一款加法和一款減法遊戲才會開放。免費、無廣告、不用註冊，題目有注音，也會念出來。
陪玩小提醒：孩子最常把 3 + 4 × 5 從左邊算成 35。可以問「乘法和加法誰先算？」；列併式時，能算出對的答案、而且故事裡每個數都用上，不同的寫法都算對。
The chameleon magician writes sums on the magic board. In level 1 children tap the step to do first (× and ÷ before + and −, otherwise left to right) and type its result until one number is left. In level 2 brackets come first, then children put a pair of brackets in so the sum makes the magician’s number. In level 3 they build one number sentence for two-step stories (including dividing twice) from number and sign cards, then write a formula for matchstick, triangle and table-seat patterns.
Suits Grade 4 (about age 9–10) in Taiwan. Taiwan curriculum (12-year basic education) units: One number sentence and the order of operations; Two-step word problems; Formulas in words and number patterns (Grade 4). It opens after one addition and one subtraction game. Free with no ads and no sign-up, read aloud. See the Taiwan elementary maths curriculum map.