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用简便方法计算:(1)5002-499×501(2)2.39×91+156×2.39-2.39×47.

题目详情
用简便方法计算:
(1)5002-499×501
(2)2.39×91+156×2.39-2.39×47.
▼优质解答
答案和解析
(1)5002-499×501
=5002-(500-1)(500+1)
=5002-(5002-1)
=1;

(2)2.39×91+156×2.39-2.39×47.
=2.39×(91+156-47)
=2.39×200
=478.