1+(-3)+5+(-7)+9+(-11)+13+(-15)
= (-2) + (-2) + (-2) + (-2)
= (-2) . 4
= (-8)
1+(-3)+5+(-7)+9+(-11)+13+(-15)
= (-2) + (-2) + (-2) + (-2)
= (-2) . 4
= (-8)
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
tính nhanh: 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= \(\dfrac{1}{9.10}-\dfrac{1}{8.9}-\dfrac{1}{7.8}-...-\dfrac{1}{2.3}-\dfrac{1}{1.2}\)
Tính số hạng có trong các tổng sau:
1) 1-2+3-4+5-6+7-8
2) 1-3+5-7+9-11+13-15
3) -1+3-5+7-9+11-13+15
Bài 1: Tính
a. 5 × -7/10
b. 4/5 × -3/22
c. 4/9 + 4/3 × 16/4
d. 11/22 - 3/9 × 14/21
Bài 2: Tính hợp lý
A = 6/13 × 5/7 + 6/13 × 2/7 + 17/13
B = 11/15 × 4/11 + 11/15 × 5/11 + 11/15 × 2/11
C = ( 19/64 - 33/22 + 24/51 ) × ( 1/5 - 1/15 - 2/15 )
D = 8/13 × 7/12 + 8/13 × 5/12 - 1/12
(13/-10 - -4/13)+11/10 A=-5/9+8/15+ -2/11 + 4/-9 + 7/15 B=10/17-5/13- -7/17 - 8/13+11/25 (3/4-1/6):2/3 (31/10-5/2).3-2 Giải chi tiết giúp bngoc ạ cmon trước💖
thực hiện phép tính :
a, A=1-3-5-7-9-11-13-15-...-97-99
b,B=1+3-5-7+9+11-13-15+...-97-99
c,C=1-3-5+7+9-11-13+15+...+97-99
d,D=-(5)-(2-7)-(5-12)-(4-6)-(-3)
mk đang cần gấp giúp mk vs nha cảm ơn nhìu
-1/9.15/22.-9/25
-2/7.(5/13-9/15)-2/7.8/13
3/10.(-4/9+2/5)-3/10.(5/9+-3/5)
4/11+-5/13+7/11+-8/13
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