1/3-3/5+5/7-7/9+9/11-11/13+13/15+11/13-9/11+7/9-5/7+3/5-1/3
Giúp mình với:
a) A=\(\dfrac{1}{3}\)-\(\dfrac{3}{5}\)+\(\dfrac{5}{7}\)-\(\dfrac{7}{9}\)+\(\dfrac{9}{11}\)-\(\dfrac{11}{13}\)+\(\dfrac{13}{15}\)+\(\dfrac{11}{13}-\dfrac{9}{11}+\dfrac{7}{9}-\dfrac{5}{7}+\dfrac{3}{5}-\dfrac{1}{3}\)
b) B= \(\dfrac{1}{9.10}-\dfrac{1}{8.9}-\dfrac{1}{7.8}-...-\dfrac{1}{2.3}-\dfrac{1}{1.2}\)
\(\frac{1}{3}-\frac{3}{5}+\frac{5}{7}-\frac{7}{9}+\frac{9}{11}-\frac{11}{13}+\frac{13}{15}+\frac{11}{13}-\frac{9}{11}+\frac{7}{9}-\frac{5}{7}+\frac{3}{5}-\frac{1}{3}\)
thực hiện phép tính hợp lí nếu có thể
Tính
1/3 - 3/5 + 5/7 - 7/9 + 9/11 - 11/13 - 9/11 + 7/9 - 5/7 + 3/5 - 1/3
thực hiện phép tính(tính nhanh nếu có thể):
a)2/13 x 5/9+3/13 x 9/11+11/13
b)5/7 x -3/11+-5/7 x 8/11+9/7
tính giá trị biểu thức sau bằng cách hợp lí
(5/4 + 3/4) . 4/7 + (3/4 + 9/4) . 4/7
-3/11 . (-22)/66 . 121/15
3/7 . 2/5 . 7/3 . 20 . 19/72
6/7 . 8/13 + 6/13 . 9/7 - 3/13 . 6/7
-1/4 . 152/11 + 68/4 . (-1)/11
-5/7 . 2/11 + (-5)/7 . 9/11 + 12/7
146/13 - (18/7 + 63/13)
cảm ơn
bài 437 Tính nhanh 13. -3/11 . -22/66 . 121/15 17. 1/3 . 4/5 + 1/3 . 6/5 18. 6/7 . 8/13 +6/13 . 9/7 - 3/13 . 6/7 19. -1/4 . 152/11 + 68/4 . -1/11 20. 3/7 . 9/26 - 1/14 . 1/13 21. 15(1/5 - 7/15) 22. 34(2và1/17 - 3và5/34)
Giúp mình với ạ
Bài 1 Tính nhanh
a) -3/7 + 5/13 + 3/7
b) -5/21+-2/21+8/24
c) -5/11+(-6/11+2)
d) (-1/32+1/2)+15/32
e)5/17+ -6/13 + 3/4 + 7/-13+12/17
f) 7/23+-18/18+-4/9+16/23+-5/8
g)1/3+-3/4+3/5+-1/36+1/15+-2/9
h)-1/2+1/3+-1/4+-2/8+4/18+4/9