1 ) chung to rang 1/2 + 1/3 + 1/4 + ....+ 1/63 > 2
2) Thực hiện phép tính: 1/56 + 2/80 + 3/130 + 4/221 + 5/374
Những câu hỏi liên quan
Thực hiện phép tính:
a/ 2/3+2/15+2/63+2/99+2/143+2/195
b/ 1/4+1/8+1/77+1/130+1/208
a) Đề thiếu nhé. sửa đề:
\(\frac{2}{3}+\frac{2}{15}+\frac{2}{35}+...+\frac{2}{195}\)
\(=\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{13.15}\)
\(=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{13}-\frac{1}{15}\)
\(=1-\frac{1}{15}\)
\(=\frac{14}{15}\)
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Thực hiện phép tính:a)
80
-
(
4
.
5
2
-
3
.
2
3
)
b)
[
36
.
4
-
4
.
(
82
-
7
.
11
)
2
]
:
4...
Đọc tiếp
Thực hiện phép tính:
a) 80 - ( 4 . 5 2 - 3 . 2 3 )
b) [ 36 . 4 - 4 . ( 82 - 7 . 11 ) 2 ] : 4 - 201 9 0
c) 5 6 : 5 4 + 2 3 . 2 2 - 1 2018
d) 303 - 3 . { [ 655 - ( 18 : 2 + 1 ) . 4 3 + 5 ] } : 10 0
a) 80-(4.52-3.23)=80-100+24=4
b)[36.4-4.(82-7.11)2]:4-20190
={4.[36-(82-7.11)2]}:4-1
=[36-(82-7.11)2]-1
=11-1=10
c)56:54+23.22-12018
=52+25-1
=25+32-1=56
d)303-3.{[655-(18:2+1).43+55]}:100
=303-3.[(655-9-1).43+55]:1
=303-3[655-640+5]
=303-3(20)
=303-60=243
Thực hiện phép tính:a,
80
-
4
.
5
2
-
3
.
2
3
b,
5
6
:...
Đọc tiếp
Thực hiện phép tính:
a, 80 - 4 . 5 2 - 3 . 2 3
b, 5 6 : 5 4 + 2 3 . 2 2 - 1 2018
c, [36.4 – 4. 82 - 7 . 11 2 ]:4 – 2019 0
d, 303 – 3.{[655 – (18:2+1). 4 3 +5]}: 10 0
a, 80 - 4 . 5 2 - 3 . 2 3
= 80 – (4.25 – 3.8)
= 80 – 76 = 4
b, 5 6 : 5 4 + 2 3 . 2 2 - 1 2018
= 5 2 + 2 5 - 1
= 25 + 32 – 1 = 56
c, [36.4 – 4. 82 - 7 . 11 2 ]:4 – 2019 0
= (144 – 4. 5 2 ):4 – 1
= (144 – 100):4 – 1
= 11 – 1 = 10
d, 303 – 3.{[655 – (18:2+1). 4 3 +5]}: 10 0
= 303 – 3.(655 – 10.64 + 5):1
= 303 – 10 = 293
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Bài 1: Thực hiện phép tính (tính nhanh nếu có thể): a) 17 . 85 + 15 . 17 - 120 b) 23 . 17 - 23 . 14c) 20 - [ 30 - (5 - 1)2 : 2] d) 80 - ( 4 . 52 - 3 . 22)e) 27 . 77 + 24 . 27 - 27 g) 174: {2 . [36 + ( 42 - 23 )]}
Đọc tiếp
Bài 1: Thực hiện phép tính (tính nhanh nếu có thể):
a) 17 . 85 + 15 . 17 - 120 b) 23 . 17 - 23 . 14
c) 20 - [ 30 - (5 - 1)2 : 2] d) 80 - ( 4 . 52 - 3 . 22)
e) 27 . 77 + 24 . 27 - 27 g) 174: {2 . [36 + ( 42 - 23 )]}
thực hiện phép tính a, (3/5+-3/4+1/20):1/2-1/2b,12/3::1/6+11/4.(1/2-1/5)c,0,75-(13/11-50%):5/11d,1/27:(-1/3)2+75%.(-22/3)Giải giúp mình với giaỉ thích : vd: -22/3 là âm 2 phần 3...
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thực hiện phép tính
a, (3/5+-3/4+1/20):1/2-1/2
b,12/3::1/6+11/4.(1/2-1/5)
c,0,75-(13/11-50%):5/11
d,1/27:(-1/3)2+75%.(-22/3)
Giải giúp mình với
giaỉ thích : vd: -22/3 là âm 2 phần 3...
d: \(\dfrac{1}{27}:\left(-\dfrac{1}{3}\right)^2+75\%\cdot\left(-\dfrac{2^2}{3}\right)\)
\(=\dfrac{1}{27}:\dfrac{1}{9}+\dfrac{3}{4}\cdot\dfrac{-4}{3}\)
\(=\dfrac{1}{3}-1\)
\(=-\dfrac{2}{3}\)
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Thực hiện phép tính:
1, -7/12. 11/8- 37/8. 7/12+ 1/2
2, ( 2/3- 1/4- 5/6 ). ( -2) mũ 2 + 3/2: -15/4
3, -2/5+ 3/10- 3/5+ 7/10- 3/2
\(\left(1\right)\dfrac{-7}{12}.\dfrac{11}{8}-\dfrac{37}{8}.\dfrac{7}{12}+\dfrac{1}{2}=-\dfrac{7}{12}.\left(\dfrac{11}{8}+\dfrac{37}{8}\right)+\dfrac{1}{2}=-\dfrac{7}{12}.6+\dfrac{1}{2}=-3.\)
\(\left(2\right)\left(\dfrac{2}{3}-\dfrac{1}{4}-\dfrac{5}{6}\right).\left(-2\right)^2+\dfrac{3}{2}:\dfrac{-15}{4}=\dfrac{-5}{12}.4-\dfrac{2}{5}=\dfrac{-5}{3}-\dfrac{2}{5}=\dfrac{-31}{15}.\)
\(\left(3\right)\dfrac{-2}{5}+\dfrac{3}{10}-\dfrac{3}{5}+\dfrac{7}{10}-\dfrac{3}{2}=1-1-\dfrac{3}{2}=-\dfrac{3}{2}.\)
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1. \(\dfrac{-7}{12}.\dfrac{11}{8}-\dfrac{37}{8}.\dfrac{7}{12}+\dfrac{1}{2}=\dfrac{-7}{12}\left(\dfrac{11}{8}+\dfrac{37}{8}\right)+\dfrac{1}{2}=\dfrac{-7}{12}.\dfrac{6}{1}+\dfrac{1}{2}=\dfrac{-7}{2}+\dfrac{1}{2}=\dfrac{-6}{2}=-3\)2.
\(\left(\dfrac{2}{3}-\dfrac{1}{4}-\dfrac{5}{6}\right).\left(-2\right)^2+\dfrac{3}{2}:\dfrac{-15}{4}=\dfrac{-5}{12}.4+\dfrac{-2}{5}=\dfrac{-5}{3}+\dfrac{-2}{5}=\dfrac{-31}{15}\)
3.
\(\dfrac{-2}{5}+\dfrac{3}{10}-\dfrac{3}{5}+\dfrac{7}{10}-\dfrac{3}{2}=\dfrac{-4}{10}+\dfrac{3}{10}-\dfrac{6}{10}+\dfrac{7}{10}-\dfrac{15}{10}=\dfrac{-15}{10}=\dfrac{-3}{2}\)
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Thực hiện phép tính:
1, -7/12. 11/8- 37/8. 7/12+ 1/2
2, ( 2/3- 1/4- 5/6 ). ( -2) mũ 2 + 3/2: -15/4
3, -2/5+ 3/10- 3/5+ 7/10- 3/2
\(\dfrac{-7}{12}.\dfrac{11}{8}-\dfrac{37}{8}.\dfrac{7}{12}+\dfrac{1}{2}=\dfrac{-7}{12}.\left(\dfrac{11}{8}+\dfrac{37}{8}\right)+\dfrac{1}{2}=-\dfrac{7}{12}.6+\dfrac{1}{2}=-\dfrac{7}{2}+\dfrac{1}{2}=-3.\)
\(\left(\dfrac{2}{3}-\dfrac{1}{4}-\dfrac{5}{6}\right).\left(-2\right)^2+\dfrac{3}{2}:\dfrac{-15}{4}=\dfrac{8-3-10}{12}.4+\dfrac{-2}{5}=\dfrac{-5}{12}.4-\dfrac{2}{5}=\dfrac{-5}{3}-\dfrac{2}{5}=-\dfrac{31}{15}.\)
\(\dfrac{-2}{5}+\dfrac{3}{10}-\dfrac{3}{5}+\dfrac{7}{10}-\dfrac{3}{2}=\left(\dfrac{3}{10}+\dfrac{7}{10}\right)+\left(\dfrac{-2}{5}-\dfrac{3}{5}\right)-\dfrac{3}{2}=1-1-\dfrac{3}{2}=\dfrac{-3}{2}.\)
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Thực hiện phép tính:
1, -7/12. 11/8- 37/8. 7/12+ 1/2
2, ( 2/3- 1/4- 5/6 ). ( -2) mũ 2 + 3/2: -15/4
3, -2/5+ 3/10- 3/5+ 7/10- 3/2
1: \(=\dfrac{7}{12}\left(-\dfrac{11}{8}+\dfrac{37}{8}\right)+\dfrac{1}{2}=\dfrac{7}{12}\cdot\dfrac{26}{8}+\dfrac{1}{2}=\dfrac{115}{48}\)
2: \(=\dfrac{8-3-10}{12}\cdot4+\dfrac{3}{2}\cdot\dfrac{-4}{15}\)
\(=\dfrac{-5}{3}+\dfrac{-12}{30}=\dfrac{-5}{3}+\dfrac{-2}{5}=\dfrac{-25-6}{15}=-\dfrac{31}{15}\)
3: \(=\dfrac{-2}{5}-\dfrac{3}{5}+\dfrac{3}{10}+\dfrac{7}{10}-\dfrac{3}{2}=-\dfrac{3}{2}\)
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Cau 1:Tinh Afrac{2000}{1}+frac{199}{2}+frac{198}{3}+......+frac{1}{2000}+200 1frac{1}{2}+frac{1}{3}+.....+frac{1}{2000} Cau 2:a,frac{1}{56}+frac{2}{80}+frac{3}{130}+frac{4}{221}+frac{5}{374}+frac{1}{506}b,frac{1}{3.4}+frac{1}{6.6}+frac{1}{9.8}+.......+frac{1}{294.198}+frac{1}{297.200}
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Cau 1:Tinh A=
\(\frac{2000}{1}+\frac{199}{2}+\frac{198}{3}+......+\frac{1}{2000}+200\)
\(1\frac{1}{2}+\frac{1}{3}+.....+\frac{1}{2000}\)
Cau 2:
a,\(\frac{1}{56}+\frac{2}{80}+\frac{3}{130}+\frac{4}{221}+\frac{5}{374}+\frac{1}{506}\)
b,\(\frac{1}{3.4}+\frac{1}{6.6}+\frac{1}{9.8}+.......+\frac{1}{294.198}+\frac{1}{297.200}\)