a, \(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}+\frac{1}{42}=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+\frac{1}{6.7}\)
= \(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}\)
= \(1-\frac{1}{7}=\frac{6}{7}\)
a) 1/2+1/4+1/8+1/16+....+1/512
b) 1/2+1/6+1/12+1/20+1/30+1/42+1/56+...+1/90+1/110
Bài 2 Tính tổng
a, 2/3 + 2/6 + 2/12 + 2/24 + 2/48 + 2/96 + 2/192
b, 1/2 + 1/4 + 1/8 + 1/18 + 1/32 + 1/64 + 1/128 + 1/256
c, 4/3x7 + 4/7x11 + 4/11x15 + 4/15x19 + 4/19x23 + 4/23x27
d, 1/2 + 5/6 + 11/12 + 19/20 + 29/30 + 41/42 + 55/56 + 71/72 + 89/90
tính nhanh các giá trị biểu thức sau
a) D = 1/2 +1/4 + 1/8 + 1/16 + 1/32
b) E = 1/2 + 1/6 + 1/12 + 1/20 + 1/30
ai trả lời nhanh và đúng mình cho tick
Bài 1: Tính nhanh
a) 1/2 + 1/4 + 1/8 + 1/16 + 1/32 + 1/128 + 1/256
b) 1/3 + 1/9 + 1/27 + 1/81 + 1/243 + 1/729
c)1/2 + 1/6 + 1/12 + 1/20 + 1/30
tính bằng 2 cách
nhanh nhé
a, 13/19 + 1 - 15/19 - 4/19
b, 3/5 +6/11 +7/13 +2/5 +16/11 +19/13
c, 1/3 +1/6 + 1/12 +1/24 +1/48
d, 1/2 +1/6 +1/12 +1/20 +1/30 +1/42
a) N = 1/2 + 1/6+ 1/12 + 1/20 + 1/30 +1/42 + 1/56 + 1/72 +1/90
b) 5/8 + 2/9 -2/5 + 3/8 + 4/9 + 1/3 - 3/5 =
c) 4 1/5 + 5 1/3 - 2 2/3 x 3 1/5 + 9/25 : 9/20 =
so sánh
a)1/2+1/6+1/12+1/20+1/30+1/42 với 60006/70707
b)1/11+1/12+1/13+1/14+.....+1/19+1/20 với 1
c)7/9+8+13 với 8/9+7/13
d)5/6+6/7+7/8+8/5 với 4
Tính nhanh:
a) 3/5 + 6/11 + 7/13 +2/5 + 16/11 + 19/13
b) 1/2 +1/6 + 1/12 + 1/20 + 1/30 + 1/42
tính nhanh:
A) 1/2 + 1/4 +4/8 + 4/10 + 1/32 + 4/64
B) 4/42 + 1/30 + 1/20 +1/6 + 1/2
C) 327 X 329 - 1 / 326+ 327 + 328
D) 1/2 + 4/4 + 4/8 + 4/10 + 1/32 + 4/64
NHANH GIÚP MÌNH NHA AI NHANH MÀ ĐÚNG THÌ MÌNH TIK!!!!