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数学门诊.(把不对的改正过来)(1)1.7×0.31+0.69×1.7=1.7×(0.31+0.69)×1.7=1.7×1×1.7=2.89改正:(2)0.25×12=0.25×(4×3)=0.25×4+0.25×3=1+0.75=1.75改正:(3)3.5×103=3.5×100+3=350+3=353改

题目详情
数学门诊.(把不对的改正过来) 
(1)1.7×0.31+0.69×1.7
=1.7×(0.31+0.69)×1.7
=1.7×1×1.7
=2.89______
改正:
(2)0.25×12
=0.25×(4×3)
=0.25×4+0.25×3
=1+0.75
=1.75______
改正:
(3)3.5×103
=3.5×100+3
=350+3
=353______
改正:
▼优质解答
答案和解析
(1)1.7×0.31+0.69×1.7
=1.7×(0.31+0.69)×1.7
=1.7×1×1.7
=2.89×
改正:1.7×0.31+0.69×1.7
=1.7×(0.31+0.69)
=1.7×1,
=1.7;

(2)0.25×12
=0.25×(4×3)
=0.25×4+0.25×3
=1+0.75
=1.75×
改正:0.25×12
=0.25×(4×3)
=(0.25×4)×3
=1×3,
=3;

(3)3.5×103
=3.5×100+3
=350+3
=353×
改正:3.5×103
=3.5×(100+3)
=3.5×100+3.5×3
=3500+10.5,
=3510.5.
故答案为:×,×,×.