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用简便方法计算(写出计算过程):385+295+105;643-12-88;125×32;8×48×125;4200÷6÷7;360÷45;125×8+275×8;99×84;25×1-25.

题目详情
用简便方法计算(写出计算过程):
385+295+105; 643-12-88; 125×32;
8×48×125; 4200÷6÷7; 360÷45;
125×8+275×8; 99×84; 25×1-25.
▼优质解答
答案和解析
(1)385+295+105
=385+(295+105)
=385+400
=785;

(2)643-12-88
=643-(12+88)
=643-100
=543;

(3)125×32
=125×8×4
=1000×4
=4000;

(4)8×48×125
=8×125×48
=1000×48
=48000;

(5)4200÷6÷7
=4200÷(6×7)
=4200÷42
=100;

(6)360÷45
=360÷9÷5
=40÷5
=8;

(7)125×8+275×8
=(125+275)×8
=400×8
=3200;

(8)99×84
=1100×84-1×84
=8400-84
=8316;

(9)25×1-25
=25-25
=0.