Các câu hỏi tương tự
(X+1)+(x+5)+(x+9)+...+(x+29)=136
(y+2)+(y+4)+(y+6)+....+(y+1996)=998000
tìm y
a, (y + 2) + (y + 4) + (y + 6) +..........+ (y + 1996) =998000
b, (1/21 - 1/30) * 140 + 1,08 : [0,2 * (y - 1)] =11
bài 1 tính
a, 24 x 66 - 24 + 36 x 24
b, 29 x 173 - 29 x 72 -29
c, 1+5+10+15+...+55+60
d, 1x2+2x3+3x4 +...+18x19+19x20
bài 2 tìm x
a,106- ( x+ 7) =9
b, 2 x ( x+ 4) + 5 =65
c, (16x x -32) x 45=0
d, x+4 x x = 100 : 5
2/1x2 + 2/2x3 + 2/3x4 + .............+ 2/18x19 + 2/19x20
1) Tính nhanh
a) 12,5 x 32 x 8
b) 20,9 + 20,9 x 99
c) 1/1x2 + 1/2x3 + 1/3x4 +.......1/49x50
2) Tìm y biết
a) 45 - 5 x (y + 1) = 10
b) y : 2 + y : 2 = 15
Tính hợp lí nếu có thể:
a)3/7+4/9+4/7+5/9
b)1/5+4/10+9/15+16/20+25/25+36/30+49/35+64/40+81/45
c)1/8+1/12+3/8+5/12
d)(1-1/2)x(1-1/3)x(1-1/4)x...x(1-100)
e)9/5:17/15+8/5:17/15
f)2/1x2+2/2x3+2/3x4+...+2/19x20
Ai nhanh nhất mình tick cho
2/1x2 + 2/2x3 +2/3x4 +...+2/18x19 + 2/19x20
a)x/3-4/y=1/5
b)4/x+y/3=5/6
c)5/x-y/3=1/6
d)x/6-2/y=1/30
Bài 3:(nâng cao) tính nhanh:
\(\dfrac{2}{1x2}\) + \(\dfrac{2}{2x3}\) + \(\dfrac{2}{3x4}\) + ........ +\(\dfrac{2}{18x19}\) + \(\dfrac{2}{19x20}\)