luotong6321
幼苗
共回答了18个问题采纳率:88.9% 举报
15页:
15×√14-6×√14
=( 15 — 6 )×√14
=9√14
19×√17×4×√17
=( 19 × 4 )×( √17 ×√17 )
=76×17
=( 1292 )
( -11 )+(+16)+(-2/5)
=+( 16 - 11 )+(-2/5)
=(+5)+(2/5)
=+( 25/5 - 2/5 )
=+( 27/5 )
(-5)×(+4/5)+(-5)×(-4/5)
=-(5×4/5)+(5×4/5)
=(-4)+( 4 )
=( 0 )
16页:
计算下列各式:
(+7.3)+(+3.7)=(7+3)+(0.3+0.7)=10+1=11
(-42)+(-16)+(+18)=[(-42)+(-16)]+18=(-58)+18=-40
0+(-39.9)=0-39.9=-39.9
(+2/5)+(-1/6)+(+2/5)+(+1/6)=[(2/5)+(2/5)]+(1/6-1/6)=4/5
能简便的简便:
5√13×4×2√13 =(5*4*2)*(√13×√13) =13*40=520
2√2-√2+10√2=√2*(2-1+10)=11√2
(-1/2)×(-2/3)×(-3/4)×(-4/5)=[(-1/2)*(-2/3)]*[(-3/4)*(-4/5)]=1/3*3/5=1/5
-(3)²×(-3)²=-(3²×3²)=-81
1年前
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