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怎样简便怎样算3.1+25.78+6.912.7-4.8-5.234.8-(4.8+9.7)15.3+4.72+4.7+5.28.

题目详情
怎样简便怎样算
3.1+25.78+6.9                  
12.7-4.8-5.2
34.8-(4.8+9.7)
15.3+4.72+4.7+5.28.
▼优质解答
答案和解析
(1)3.1+25.78+6.9
=3.1+6.9+25.78
=10+25.78
=35.78                 
(2)12.7-4.8-5.2
=12.7-(4.8+5.2)
=12.7-10
=2.7
(3)34.8-(4.8+9.7)
=34.8-4.8-9.7
=30-9.7
=20.3
(4)15.3+4.72+4.7+5.28
=(15.3+4.7)+(5.28+4.72)
=20+10
=30