(1) (-8)+10+2+(-1) =2+2+(-1) =4+(-1) =3 (2) 5+(-6)+3+9+(-4)+(-7) =(-1)+3+9+(-4)+(-7) =2+9+(-4)+(-7) =11+(-4)+(-7) =7+(-7) =0 (3) (-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5 =0.4+(-0.7)+(-2.1)+0.8+3.5 =(-0.3)+(-2.1)+0.8+3.5 =(-0.09)+0.8+3.5 =4.12 (4) 2/1+(-3/2)+

来源：学生作业帮助网编辑：作业帮时间：2024/04/19 15:25:40

(1) (-8)+10+2+(-1) =2+2+(-1) =4+(-1) =3 (2) 5+(-6)+3+9+(-4)+(-7) =(-1)+3+9+(-4)+(-7) =2+9+(-4)+(-7) =11+(-4)+(-7) =7+(-7) =0 (3) (-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5 =0.4+(-0.7)+(-2.1)+0.8+3.5 =(-0.3)+(-2.1)+0.8+3.5 =(-0.09)+0.8+3.5 =4.12 (4) 2/1+(-3/2)+
(1)
(-8)+10+2+(-1)
=2+2+(-1)
=4+(-1)
=3
(2)
5+(-6)+3+9+(-4)+(-7)
=(-1)+3+9+(-4)+(-7)
=2+9+(-4)+(-7)
=11+(-4)+(-7)
=7+(-7)
=0
(3)
(-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5
=0.4+(-0.7)+(-2.1)+0.8+3.5
=(-0.3)+(-2.1)+0.8+3.5
=(-0.09)+0.8+3.5
=4.12
(4)
2/1+(-3/2)+5/4+(-2/1)+(-3/1)
=30/15+(-30/20)+30/24+(-30/15)+(-30/10)
=(-30/5)+30/24+(-30/15)+(-30/10)
=30/19+(-30/15)+(-30/10)
=30/4+(-30/10)
=-30/6
大家看我做的对么!

(-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5
=0.4+(-0.7)+(-2.1)+0.8+3.5
=(-0.3)+(-2.1)+0.8+3.5
=(-0.09)+0.8+3.5
=4.12 这个不对应该是
(-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5
=0.4+(-0.7)+(-2.1)+0.8+3...

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(-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5
=0.4+(-0.7)+(-2.1)+0.8+3.5
=(-0.3)+(-2.1)+0.8+3.5
=(-0.09)+0.8+3.5
=4.12 这个不对应该是
(-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5
=0.4+(-0.7)+(-2.1)+0.8+3.5
=(-0.3)+(-2.1)+0.8+3.5
=(-2.4)+0.8+3.5
=(-1.6)+3.5
=1.9
2/1+(-3/2)+5/4+(-2/1)+(-3/1)
=30/15+(-30/20)+30/24+(-30/15)+(-30/10)
=(-30/5)+30/24+(-30/15)+(-30/10)
=30/19+(-30/15)+(-30/10)
=30/4+(-30/10)
=-30/6
这个也不对，第二步就错了,其实这道题可以通过移项解决
2/1+(-3/2)+5/4+(-2/1)+(-3/1)
=2/1+(-2/1)+(-3/2)+(-3/1)+5/4
=0+(-3/2)+(-6/2)+5/4
=(-9/2)+5/4
=(-18/4)+5/4
=-13/4

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对了`诶```

第（1）（2）对了
第（3）（4）错了
(3)
(-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5
=0.4+(-0.7)+(-2.1)+0.8+3.5
=(-0.3)+(-2.1)+0.8+3.5
=(-2.4)+0.8+3.5
=(-1.6)+3.5
=1.9
(4)
2/1+(-3/2)...

全部展开

第（1）（2）对了
第（3）（4）错了
(3)
(-0.8)+1.2+(-0.7)+(-2.1)+0.8+3.5
=0.4+(-0.7)+(-2.1)+0.8+3.5
=(-0.3)+(-2.1)+0.8+3.5
=(-2.4)+0.8+3.5
=(-1.6)+3.5
=1.9
(4)
2/1+(-3/2)+5/4+(-2/1)+(-3/1)
=30/15+(-30/20)+30/24+(-30/15)+(-30/10)
=(-30/5)+30/24+(-30/15)+(-30/10)
=30/19+(-30/15)+(-30/10)
=30/4+(-30/10)
=-30/6
=-5/1

收起

(10+1)(10^2+1)(10^4+1)(10^8+1).(10^32+1)=? 8+3=2,10+1=1求8+8=? x乘以{1-3/8}=2除以1/10 数学题：1/2+1/4+1/8+1/16+.+1/2n（n=10） -1+()=-1 -10+()=0 -4+()=-8 -2+()=+12-1+()=-1 -10+()=0-4+()=-8 -2+()=+12 （x+2）/（10x-2）=8/1 有规律的相加求和.1+1/2+2+1/4+3+1/8+...+10+1/2^10 = 阅读下题的解法,并完成提问1.(2+1)(2^2+1)(2^4+1)-2^8原式=(2-1)(2+1)(2^2+1)(2^4+1)-2^8=(2^2-1)(2^2+1)(2^4+1)-2^8=(2^4-1)(2^4+1)-2^8=(2^8-1)-2^8=-12.照1里的解法计算(10^2+1)(10^4+1)(10^8+1)*9900+100是多少? 2=1/7*()=1/8*( )=1/9*()=1/10+()=1*100%要快 2/3+9/10+3/2+10/9+4/8+1+2/1= 根据例子计算计算2/1+4/1+8/1可以这样考虑：2/1=1-2/1,4/1=2/1-4/1/,8/4=4/1-8/12/1+4/1+8/1=（1-2/1）+（2/1-4/1）+（4/1-8/1）=1-8/1=8/7求1 2/1+2 4/1+3 8/1+4 16/1+5 32/1+.+10 1024/1 1/2*4+1/6*8+.1/2006*2008+1/4*6+1/8*10+.1/2004*2006=? 已知2/1-4/1=4/1,4/1-8/1=8/1,8/1-16/1=16/1,你能不通分算出2/1+4/1+8/1+16/1的和吗?10^-^ 1/4+(2+1/10)+(4+1/18)+(6+1/28)+(8+1/40)+(10+1/54)=? 1+1/2+1/4+1/8+.+1/2的9次方+1/2的10次方= 7/10-3/8-1/8+1/2简便运算 = = 1/2x(6+8+10)=1/2*6*8怎么算的 1+2+34+5+6+7+8+9+10=?