题目内容
用简便的方法计算;
①283-47-153 ②842-368-132 ③273-98
④267+153+433 ⑤782-216-184 ⑥472-127-123.
①283-47-153 ②842-368-132 ③273-98
④267+153+433 ⑤782-216-184 ⑥472-127-123.
分析:①、②、⑤、⑥可根据“a-b-c=a-(b+c)”这一规律进行简便计算;
③可把98拆成100-2来计算简便;
④可运用加法交换律来计算.
③可把98拆成100-2来计算简便;
④可运用加法交换律来计算.
解答:解:①283-47-153
=283-(47+153)
=283-200
=83;
②842-368-132
=842-(368+132)
=842-500
=342;
③273-98
=273-(100-2)
=273-100+2
=175;
④267+153+433
=267+433+153
=700+153
=853;
⑤782-216-184
=782-(216+184)
=782-400
=382;
⑥472-127-123
=472-(127+123)
=472-250
=222;
故答案为83;342;175;853;382;222.
=283-(47+153)
=283-200
=83;
②842-368-132
=842-(368+132)
=842-500
=342;
③273-98
=273-(100-2)
=273-100+2
=175;
④267+153+433
=267+433+153
=700+153
=853;
⑤782-216-184
=782-(216+184)
=782-400
=382;
⑥472-127-123
=472-(127+123)
=472-250
=222;
故答案为83;342;175;853;382;222.
点评:此题是考查简便计算,要仔细观察算式的特点,灵活运用一些定律进行简便计算.
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