tính nhanh:
1/90:0.25+1/90:0.2+1/90:0.5+1/90:0.125-1/90:0.1
[1000*0.1-900*0.1-90*0.1]*[142*0.5-240*0.25]
A=((1000-900-90)*0.1)*(142*0.5-240*0.5*0.5)
A=(10*0.1)*((142-120)*0.5)
A=1*22*0.5=11
(1000+0,1-900×0,1-90×0,1)(142×0,5-240×0,25)=1×11=11
(100*0.1-900*0.1-90*0.1)*(142*0.5-240*0.25)=?
( 100 x 0,1 - 900 x 0,1 -90 x 0,1 ) x (142 x 0,5 - 240 x 0,25 )
=(10 - 90 - 9 ) x ( 71 - 60 )
= -89 x 11
= -979
tính nhanh
1/2:0.5-1/4|:0.25+1/8:0.125-1/10:0.1
Tính nhanh 1/90:0,25 +1/90:0,2 +1/90 :0,5 +1/90:0,125-1/90 :0,1
=1.4/90+1.5/90+1.2/90+1.10/90
=4/90+5/90+2/90+10/90
=4+5+2+10/90
=21/90
=7/30
1/90:0,25 +1/90:0,2 +1/90 :0,5 +1/90:0,125-1/90 :0,1
=1/90 : ( 0,25 + 0,2 + 0,5 + 0,125 - 0,1 )
= 1/90 : 0,975
= 1/90 : 975/100
= 1/90 : 39/4
= 2/1755
tinh nhanh
1/2/0.5-1/4/0.25+1/8/0.125-1/10/0.1
1/2:0.5-1/4:0.25+1/8:0.125-1/10:0.1
1/2 : 0.5 - 1/4 : 0.25 + 1/8 : 0.125 - 1/10 : 0.1
1/2 : 0.5 - 1/4 : 0.25 + 1/8 : 0.125 - 1/10 : 0. 1
= 1 - 1 + 1 - 1
= 0 + 0
= 0
\(\frac{1}{2}:0,5-\frac{1}{4}:0,25+\frac{1}{8}:0,125-\frac{1}{10}:0,1\)
\(=\frac{1}{2}:\frac{1}{2}-\frac{1}{4}:\frac{1}{4}+\frac{1}{8}:\frac{1}{8}-\frac{1}{10}:\frac{1}{10}\)
\(=1-1+1-1=0\)
1/2:0.5-1/4:0.25+1/8:0.125-1/10:0.1
1/2:0.5-1/4:0.25+1/8:0.125-1/10:0.1
1/2:0,5-1/4:0,25+1/8:0,125-1/10:0,1
=1-1+1-1
=0