1、8÷38×5.7+2.5÷3 2、39×(31/56+7/22)+17×(31/56-7/22) (写出过程)

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1、8÷38×5.7+2.5÷3 2、39×(31/56+7/22)+17×(31/56-7/22) (写出过程)
1、8÷38×5.7+2.5÷3 2、39×(31/56+7/22)+17×(31/56-7/22) (写出过程)

1、8÷38×5.7+2.5÷3 2、39×(31/56+7/22)+17×(31/56-7/22) (写出过程)
8÷38×5.7+2.5÷3
=4/19x5.7+5/2x1/3
=1.2+5/6
=6/5+5/6
=36/30+25/30
=61/30
39×(31/56+7/22)+17×(31/56-7/22)
=39x31/56+39x7/22+17x31/56-17x7/22
=(39+17)x31/56+(39-17)x7/22
=56x31/56+22x7/22
=31+22
=53

8÷38×5.7+2.5÷3=(8/38)*(57/100)+5/6=6/5+5/6=61/30
39×(31/56+7/22)+17×(31/56-7/22)
=(39+17)×(31/56)+(39-17)*7/22
=31+7=38