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神机妙算细又巧.(计算下面各题能简算的要简算)(1)21.28-21.28÷7×3(2)0.32×25×12.5(3)2.5×4.7-2.5+2.5×6.3(4)(77.4-3.096÷0.4)÷0.03(5)7.74×(2.8-1.3)+1.5×2.26

题目详情
神机妙算细又巧.(计算下面各题能简算的要简算)
(1)21.28-21.28÷7×3         
(2)0.32×25×12.5        
(3)2.5×4.7-2.5+2.5×6.3     
(4)(77.4-3.096÷0.4)÷0.03                
(5)7.74×(2.8-1.3)+1.5×2.26.
▼优质解答
答案和解析
(1)21.28-21.28÷7×3,
=21.28-3.04×3,
=21.28-9.12,
=12.16;

(2)0.32×25×12.5,
=0.8×0.4×25×12.5,
=(0.8×12.5)×(0.4×25),
=10×10,
=100;

(3)2.5×4.7-2.5+2.5×6.3,
=2.5×(4.7-1+6.3),
=2.5×10,
=25;

(4)(77.4-3.096÷0.4)÷0.03,
=(77.4-7.74)÷0.03,
=69.66÷0.03,
=2322;

(5)7.74×(2.8-1.3)+1.5×2.26,
=7.74×1.5+1.5×2.26,
=1.5×(7.74+2.26),
=1.5×10,
=15.