简便运算4-3.5-[(-2.5-1.2+4)-6.9]=?3.75-[(-8分之3)+(-2分之1)-(-6分之5)+4又3分之2]-0.125=?guo cheng

4-3.5-[(-2.5-1.2+4)-6.9]=0.5-(0.3-6.9)=0.5-(-6.6)=7.1
3.75-[(-8分之3)+(-2分之1)-(-6分之5)+4又3分之2]-0.125
=15/4-(-3/8-1/2+5/6+14/3)-1/8
=15/4+3/8+1/2-5/6-14/3-1/8
=15/4+(3/8-1/8)+1/2-(5/6+14/3)
=15/4+1/4+(1/2-11/2)
=4-5
=-1

7.1

4-3.5-[(-2.5-1.2+4)-6.9]
=4-3.5+2.5+1.2-4+6.9
=(4-4)-(3.5-2.5-1.2)+6.9
=0.2+6.9
=7.1
3.75-[(-8分之3)+(-2分之1)-(-6分之5)+4又3分之2]-0.125
=3.75+8分之3+2分之1-6分之5-4又3分之2-0.125
=8分之3-0.125+0.75+(3-4又3分之2)+(2分之1-6分之5)
=0.25+0.75-1又3分之2-3分之1
=-1

4-3.5-[(-2.5-1.2+4)-6.9]=10.1
3.75-[(-8分之3)+(-2分之1)-(-6分之5)+4又3分之2]-0.125=-1.1

1、4-3.5-[(-2.5-1.2+4)-6.9]=4-4-3.5+2.5+1.2+6.9=7.12、3.75-[(-8分之3)+(-2分之1)-(-6分之5)+4又3分之2]-0.125=3+3/4+3/8+1/2-5/6-4-2/3-1/8=(3-4)+[3/4+(3/8-1/8)]+(1/2-5/6-2/3)=-1+1+3/6-5/6-4/6=-6/6=-1...

1>
4-4-(3.5-2.5)+1.2+6.9=-1+1.2+6.9=7.1
2>
=3+3/4+3/8+1/2-5/6-4-2/3-1/8
=3-4+[(3/8-1/8)+3/4]-5/6-2/3
=-1+1-(5/6+4/6)
=-3/2
-1又2分之1