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用简便方法计算 487-187-139-61      &n

来源:学生作业帮 编辑:拍题作业网作业帮 分类:综合作业 时间:2024/04/30 08:15:26
用简便方法计算
487-187-139-61         38×101            1825-(625+90) 12×29+12         
58×197+58×3             125×(80+8) 101×56-56          79×34+34          
125×48 (80+8)×25           32×(200+3) 38×39+38
94+38+106+62         125×15×8               25×32×125 125÷25×8              
125×48               989-186-14 4600÷25÷4           136×101-136       
32×37+47×37+21×37 99×77+77            99×8                 78×37-37×68.
(1)487-187-139-61        
=(487-187)-(139+61)
=300-200
=100;

(2)38×101
=38×(100+1)
=38×100+38
=3838;
                      
(3)1825-(625+90)
=(1825-625)-90 
=1200-90
=1110;

(4)12×29+12
=12×(29+1)
=12×30
=360;

(5)58×197+58×3
=58×(197+3)
=58×200
=11600;

(6)125×(80+8)
=125×80+8×125
=10000+1000
=11000;

(7)101×56-56
=(101-1)×56
=100×56
=5600;

(8)79×34+34
=(79+1)×34
=80×34
=80×(30+4)
=2400+320
=2720;

(9)125×48
=125×(8×6)
=(125×8)×6
=1000×6
=6000;

(10)(80+8)×25
=25×80+8×25
=2000+100
=2100;

(11)32×(200+3)
=32×200+3×32
=6400+96
=6496;

(12)38×39+38
=38×(39+1)
=38×40
=1520;

(13)94+38+106+62
=(94+106)+(38+62)
=200+100
=300;

(14)125×15×8 
=(125×8)×15
=1000×15
=15000;

(15)25×32×125
=25×4×8×125
=(25×4)×(8×125)
=100×1000
=100000;

(16)125÷25×8 
=5×8 
=40;

(17)125×48
=(125×8)×6
=1000×6
=6000;

(18)989-186-14
=989-(186+14)
=989-200
=789;

(19)4600÷25÷4
=4600÷(25×4)
=4600÷100
=46;

(20)136×101-136
=136×(101-1)
=136×100
=13600;

(21)32×37+47×37+21×37
=(32+47+21)×37
=100×37
=3700;

(22)99×77+77
=(99+1)×77
=100×77
=7700;

(23)99×8
=(100-1)×8
=100×8-8
=800-8
=792;

(24)78×37-37×68
=(78-68)×37
=10×37
=370.