= 1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13+1/13-1/15
= 1/3-1/15
=4/15
= 1/3-1/5+1/5-1/7+1/7-1/9+1/9-1/11+1/11-1/13+1/13-1/15
= 1/3-1/15
=4/15
-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
(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💖
2/(3*5)+2/(5*7)+2/(7*9)+2/(9*11)+2/(9*13)+2/(13*15)
A -17/30 + 11/15 - 7/12
1/2+3/4-(3/4-4/5)
-7/25×11/13+ -7/25×2/13-18/25
(-3,2)+ -15/64+(0,8-2 4/15)÷3 2/3
-5/9+5/9÷(1 2/3- 2 1/12)
-5/7×2/11+ -5/7×9/11+ 1 5/7
(3/8+ -3/4+7/12)÷5/6+1/2
50%×1 1/3×10×7/35×0,75
Mn giúp mk với
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
Bài 2: thực hiện phép tính bằng cách hợp lý
a. A=(1/2-7/13-1/3)+(-6/13+1/2+1và1/3)
b.B=0,75+2/5+(1/9-1và1/2+5/4)
c.(-5/9).3/11+(-13/18).3/11
d.(-2/3).3/11+(-16/9).3/11
e.(-1/4).(-2/13)-7/24.(-2/13)
f.(-1/27).3/7+(5/9).(-3/7)
g.(-1/5+3/7):2/11+(-4/5+4/7):2/11
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 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