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简便① 3.6÷0.4-1.2X5 ②90÷(3.6-1.8)③(31.6-11.7)÷2.5÷0.4 ④3.4X7.8

来源:学生作业帮 编辑:大师作文网作业帮 分类:数学作业 时间:2024/11/15 19:10:51
简便① 3.6÷0.4-1.2X5 ②90÷(3.6-1.8)③(31.6-11.7)÷2.5÷0.4 ④3.4X7.8÷3.9 ⑤2.23X4+4.77÷0.25
简便① 3.6÷0.4-1.2X5 ②90÷(3.6-1.8)③(31.6-11.7)÷2.5÷0.4 ④3.4X7.8
① 3.6÷0.4-1.2X5
=1.2X(3÷0.4)-1.2X5
=1.2X(7.5-5 )
=1.2X2.5
=0.3X(4X2.5)
=0.3X10
=3
②90÷(3.6-1.8)
=90÷1.8
=5X(18÷1.8)
=5X10
=50
③(31.6-11.7)÷2.5÷0.4
=(31.6-11.7)÷(2.5X0.4 )
=19.9÷1
=19.9
④3.4X7.8÷3.9
=3.4X2X(3.9÷3.9 )
=6.8X1
=6.8
⑤2.23X4+4.77÷0.25
=2.23X4+(4.77X4)÷(0.25X4)
=2.23X4+(4.77X4)÷1
=2.23X4+4.77X4
=(2.23+4.77)X4
=7X4
=28