[求助] 整數四則運算去掉括號後"+"要變成"-"?
我想請問最近在教6年級的小朋友整數的四則運算
例如:
55-(20-19) = 55-20+19
我的學生的算法是 :
step1. 20-19=1
step2. 55-1=54
但是他不能理解:
為什麼55-(20-19)的括號去掉之後,
括號內的"+"要便要變成"-"
雖然我覺得他的算法就很正確了
會這樣就夠了
但是學校老師要求也要能看出原式=55-20+19
請問有什麼比較具體的解說方式能讓他了解呢?
感激不盡!!
PS 我有爬文看到版上一篇相關討論"去掉括號要變號"
但是還是沒有找到理想方式
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※ 編輯: sisvdk 來自: 180.218.247.60 (09/26 12:33)
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