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简便运算,一共6道2.5×(1.9+1.9+1.9+1.9) 5/9-3/8+11/18-5/8 7/29×3/8+6/

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简便运算,一共6道
2.5×(1.9+1.9+1.9+1.9) 5/9-3/8+11/18-5/8 7/29×3/8+6/29×7/12+3/29×7/9 1999+999² 1999÷1999又2000分之1999+1/2001 999又9分之8+99又9分之8+9又9分之8+3分之1
简便运算,一共6道2.5×(1.9+1.9+1.9+1.9) 5/9-3/8+11/18-5/8 7/29×3/8+6/
2.5×(1.9+1.9+1.9+1.9)
=2.5X4X1.9
=10X1.9
=19
5/9-3/8+11/18-5/8
=(5/9+11/18)-(3/8+5/8)
=7/6-1
=1/6
7/29×3/8+6/29×7/12+3/29×7/9
=7/29x3/8+7/29x1/2+7/29x1/3
=7/29x(3/8+1/2+1/3)
=7/29x 29/24
=7/24
1999+999²
=1000+999+999x999
=1000+999x(999+1)
=1000+999000
=1000000
1999÷1999又2000分之1999+1/2001
=1999÷【1999(1+1/200)】+1/2001
=1÷(1+1/2000)+1/2001
=2000/2001+1/2001
=1
999又9分之8+99又9分之8+9又9分之8+3分之1
=1000-1/9+100-1/9+10-1/9+1/3
=1110+(1/3-1/9x3)
=1110+0
=1110
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