U1-U3 review

   1. https://kahoot.it/challenge/0546197?challenge-id=5d3539e2-6149-4988-80c6-973e8147a81a_1742515307829 (kahoot) 

2. https://play.blooket.com/play?hwId=67dcad09307cb875f3aedf5c (賣東西)

3. https://play.blooket.com/play?hwId=67dcad6ad4a9b036a4a8e9d3 (卡片對戰,難一點)