\(=2\cdot\left(\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+...+\dfrac{1}{53}-\dfrac{1}{55}\right)=2\cdot\dfrac{10}{55}=\dfrac{20}{55}=\dfrac{4}{11}\)
Tính hợp lý:
a, -3/4 + 3/7 + -1/4 + 4/9 + 4/7
b, -7/9 x 4/11 + -7/9 x 7/11 + 5 và 7/9
c, ( 21/31 + 2013/6039 ) - ( 44/53 - 10/31) - /53
Tính các tổng sau:
1, S=1-2+3_4+..+25-26
2, S=1-3+5-7+...+49-51
3, S=-1+3-5+7-...-53+55
4, S=2-4+6-8+...+22-24
5, S=-2+4-6+8-...-26+28
6, S=2-5+8-11+...-29+32
7, S=-1+5-9-13-...-41-45
8, S=1-5+9-13+...++89-93
9, S=2-4+6-8+...+202-204
10, S=1-6=11-16+21-26+...+171-176
huhu giúp mình với ạ 2h chiều nay mình phải nộp r =(((
Tính hợp lý:
a) -3/4 + 3/7 + -1/4 + 4/9 + 4/7
b) -7/9 . 4/11 + -7/9 . 7/11 + 5 7/9(hỗn số)
c) (21 /31 + 2013 + 6039) - ( 44/33 - 10/31) - 9/53
CÁC BN GIÚP MK , MK SẼ TICK.
Bài 1:thực hiện phép tính(hợp lí nếu có thể):
1, -5/12 x 2/11 + -5/12 x 9/11 + 5/12
2, -3/5 : 7/5 - 3/5 : 7/5 + 2 3/5
3, 1/2+ 3/4 - ( 3/4 - 4/5)
4, 2/3 + 1/3 x ( -4/9 + 5/6)
5, -3/7 x 5/9 + 4/9 x -3/7 + ( - 2022) ^ 0
6,0,75 - ( 2 1/3 + 0,75) + 3 ^ 2 x ( -1/9)
7, 2 6/7 x [(-7/5 - 3/2 : -5/-4) + ( 3/2)^2]
8,2/7 + 5/7 x ( 3/5 - 0,25 ) x ( -2)^2 + 35%
9, 1 13/15 x 0,75 - ( 11/20 + 25%): 1 2/5
10, ( -2,4 + 1/3 ) : 3 1/10 + 75% : 1 1/2
11.5/3 - 5/7 + 5/9 / 10/3 - 10/7 + 10/9
1, -5/6 - 3/10
2, -1/3 + -3/4 - 2/5
3,-2/9 - 11/6 -7/12
4, 2/5 - -7/10 -4/15
Tính hợp lí:
a, \(\frac{-3}{4}+\frac{3}{7}+\frac{-1}{4}+\frac{4}{9}+\frac{4}{7}\)
b, \(\frac{-7}{9}.\frac{4}{11}+\frac{-7}{9}.\frac{7}{11}+5\frac{7}{9}\)
c,\(\left(\frac{21}{31}+\frac{2013}{6039}\right)-\left(\frac{44}{53}-\frac{10}{31}\right)-\frac{9}{53}\)
giúp mik vs mik cần gấp lắm
1. [ ( -2 ). 3 + 9 ]. ( -5 ) - ( -6 ). 8
2. ( 135 - 35 ). ( -47 ) + 53. ( -48 - 52 )
3. 0 - 1 + 2 - 3 + 4 - 5 + 6 - 7 + ... + 2004 - 2005
4. 1 - 3 + 5 - 7 + 9 - 11 + ... + 2005 - 2007
5.1 + 2 + 3 - 4 - 5 - 6 + 7 + 8 + 9 - 10 - 11 - 12 + ... + 97 + 98 + 99 - 100 - 101 - 102
a) 1/2 - 5/6 + 11/33 - 35/40
b) 2/3 . 1 3/4 - 8/9 - 17/51 - 1/5
c) 1/2 . 2 - 2 5/7 + 6/4 - 10/15
d) 1/6 . 1/11 + 4/11 . ( -1/6) + 8/11 . 1/6 + 1/6 . 6/11
e) -17 . (-23) + (-53) . 17 +17 . 14 + 17 .(-24)
f) -19,218 + (-82) .19 - 533 . 19 + (-19) . 167
g) 2/5 + 3/8 - 11/44 + 9/16
h) 4/10 - 1 5/6 . 2 + 7/8 -1/9
i ) 3. 1/5 - 2/8 - 12/36 + 15/9
k) 6/8 . 3 1/2 + 4 2/3 - 11/55 + 17/51
l ) 1/3 . 3 1/2 - 4 2/5 - 26/78 + 17/51
TÌM Y
1) [( 3/8*y-1/2): 5/7+4/9 ]*6/11=18/55
2) ( 7/10-3*y):(1 9/10-1 2/5)+4/5=1
