`[1]`
`= (3/2 - 1/2) : 9 + 1/3 - 1/6`
`= 1 : 9 + 1/3 - 1/6`
`= 1/9 + 1/3 - 1/6`
`= 5/18`
`b, 3/7 . 26 1/3 - 37 1/3 - 2/5`
`= 79/7 - 37 1/3 - 2/5`
`= -547/21 - 2/5`
`= -2777/105`
Thuc hien phep tinh hop li(neu co the):
1) 3.52 - 16 : 22
2) 23 .17 -23 . 14
3) 17.85 + 15.17 - 120
4) 20 - [30-(5 - 1)2]
5) 36 . 32 + 23 .22
6) 17 .85 + 15.17 - 120 + 20120
7) 37. 24 + 37. 76 + 63 . 79 + 21. 63
bài 1 tính bằng cách hợp lí nếu có thể
\(\frac{-5}{12}\)-\(\frac{-3}{24}\)=
b) 5\(\frac{5}{13}\)-(1\(\frac{1}{2}+3\frac{5}{13}\))
c)\(\frac{-13}{37}.\frac{5}{23}+\frac{-13}{37}.\frac{18}{23}+\frac{50}{37}\)
d)(0,5 -\(\frac{3}{2}\)):1\(\frac{1}{6}+75\%\)
bài 2 tìm x biết
-7/5 +x = -3/4
-7/4 + 1/4 : x = 3/2
Chứng minh rằng:
a) A=1+1/2^2+1/3^2+1/4^2+...+1/100^2 bé hơn 2
b) B=1+1/2+1/3+1/4+...+1/63 bé hơn 6
c)M=1/3+1/31+1/35+1/37+ 1/47+1/53+1/61 bé hơn 1/2
d)C=1/2.3/4.5/6....9999/10000 bé hơn 1/100
a ) A=2^100 -2^99 -2^98 -...-2^2-2-1
b) 1/1*2*3 +2*3*4 +1/3*4*5+...+1/36*37*38 +1/37*38*39
tính:
-66.(\(\frac{1}{2}-\frac{1}{3}+\frac{1}{11}\))+124.(-37)+63.(-1+24)
Tính hợp lý
a.) 19.(-37)+(-19).63
b.) -2 2/5 - (1 2/9 - 3 2/5)
Xin mọi người giúp mai mị thi
tìm x:
a) 1/2.x+3/5.(x-2)= 3
b)1/3.x-0,5.x= 0,75
c)3/-2.x-0,5.x=75%
d)-2/5.x+1/4=75%-3/4.x
cach tinh bai : 1/1*2*3+1/2*3*4+1/3*4*5+...+1/37*38*39
Thực hiện phép tính:
a.0,3-4/9:4/3.6/5+1
b.1+2:(2/3-1/6).(-2,25)
c.[(1/4-0,5).2+8/3]:2
d.[(3/8-5/12).6+1/3].4
e.(4/5-1):3/5-2/3.0,5
f.0,8:{0,2-7.[1/6+(5/21-5/14)]}
thực hiện dãy tính
(3 2/5 - 2 2/5). (-5/3) + . ( 2 /1/2 : 1/2)
1 13/15 . (0,5)2 . 3 + ( 8/15 + 1 19/60) : 1 23/24
