Luyện tập các phép tính về phân số và số thập phân
Các câu hỏi tương tự
D= 1+\(\frac{1}{3}\)+\(\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^n}\)
G= (1-\(\frac{1}{2}\)) . ( 1-\(\frac{1}{3}\)) . (1-\(\frac{1}{4}\))....(1-\(\frac{1}{2015}\)
1. tinh` giá trị biểu thức ( tính nhanh nếu có thế )
a)frac{-6}{11}.frac{5}{13}+frac{-6}{11}.frac{8}{13}-left(frac{-2}{5}right)^0 b)left(2frac{2}{3}+3frac{1}{2}right);left(4frac{3}{4}-2frac{1}{6}right)+frac{19}{31} c)2,4:left(-2right)^3+left(3-frac{9}{11}right).1frac{3}{8}
d)left(-frac{3}{4}right)^2:frac{-3}{8}+frac{1}{2}-frac{3}{4}-left(frac{-78}{57}right)^0
2. tìm x
a)x+frac{-1}{5}left(-frac{3}{4^{ }}right)^2 b)left|frac{5}{2}x+frac{2}{3}right|-frac{1}{4}0...
Đọc tiếp
1. tinh` giá trị biểu thức ( tính nhanh nếu có thế )
\(a)\frac{-6}{11}.\frac{5}{13}+\frac{-6}{11}.\frac{8}{13}-\left(\frac{-2}{5}\right)^0\) \(b)\left(2\frac{2}{3}+3\frac{1}{2}\right);\left(4\frac{3}{4}-2\frac{1}{6}\right)+\frac{19}{31}\) \(c)2,4:\left(-2\right)^3+\left(3-\frac{9}{11}\right).1\frac{3}{8}\)
\(d)\left(-\frac{3}{4}\right)^2:\frac{-3}{8}+\frac{1}{2}-\frac{3}{4}-\left(\frac{-78}{57}\right)^0\)
2. tìm x
\(a)x+\frac{-1}{5}=\left(-\frac{3}{4^{ }}\right)^2\) \(b)\left|\frac{5}{2}x+\frac{2}{3}\right|-\frac{1}{4}=0\) \(c)\frac{2}{3}x-\frac{1}{2}=\frac{5}{12}+\frac{1}{2}x\) \(d)\left(x-\frac{1}{4}\right)^4=\frac{1}{81}\)
\(e)4x+3\frac{1}{4}=x-\frac{1}{4}\) \(g)\left(x-\frac{1}{3}\right)^3=\frac{1}{27}\)
Bài 5 : Chững minh rẳng :
a) S frac{3}{10}+frac{3}{11}+frac{3}{12}+frac{3}{13}+frac{3}{14} CMR :1 S 2
b) frac{1}{4^2}+frac{1}{6^2}+frac{1}{8^2}+frac{1}{10^2}+...+frac{1}{left(2nright)^2} frac{1}{4}
c) frac{3}{4}+frac{8}{9}+frac{15}{16}+...+frac{2499}{2500}48
d) frac{1}{5}+frac{1}{13}+frac{1}{14}+frac{1}{15}+frac{1}{61}+frac{1}{62}+frac{1}{63} frac{1}{2}
Bài :So sánh phân số sau:
a)frac{1985.1987-1}{1980+1985.1986}và1
b) A frac{13^{15}+1}{13^{16}+1}và...
Đọc tiếp
Bài 5 : Chững minh rẳng :
a) S= \(\frac{3}{10}+\frac{3}{11}+\frac{3}{12}+\frac{3}{13}+\frac{3}{14}\) CMR :1< S <2
b) \(\frac{1}{4^2}+\frac{1}{6^2}+\frac{1}{8^2}+\frac{1}{10^2}+...+\frac{1}{\left(2n\right)^2}< \frac{1}{4}\)
c) \(\frac{3}{4}+\frac{8}{9}+\frac{15}{16}+...+\frac{2499}{2500}>48\)
d) \(\frac{1}{5}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{61}+\frac{1}{62}+\frac{1}{63}< \frac{1}{2}\)
Bài :So sánh phân số sau:
a)\(\frac{1985.1987-1}{1980+1985.1986}và1\)
b) A= \(\frac{13^{15}+1}{13^{16}+1}\)và B = \(\frac{13^{16}+1}{13^{17}+1}\)
c)\(\frac{18}{53}và\frac{26}{79}\)
d)\(\frac{5}{8}và\frac{14}{17}\)
e)\(\frac{1}{5^{199}}và\frac{1}{3^{300}}\)
g)\(\frac{1}{3^{17}}và\frac{1}{5^{10}}\)
h) \(\frac{18}{109}và\frac{5}{30}\)
a,frac{3}{4}-x1 b,x+4frac{1}{5} c,x-frac{1}{5}2
d,x+frac{5}{3}frac{1}{81} e,x-frac{10}{3}frac{7}{15}.frac{3}{5} g,x+frac{3}{22}frac{27}{121}.frac{11}{9}
h,1-xfrac{49}{65}.frac{5}{7} i,frac{8}{23}.frac{46}{24}-xfrac{1}{3} k,frac{62}{7}.xfrac{29}{9}:frac{3}{56}
Đọc tiếp
\(a,\frac{3}{4}-x=1\) \(b,x+4=\frac{1}{5}\) \(c,x-\frac{1}{5}=2\)
\(d,x+\frac{5}{3}=\frac{1}{81}\) \(e,x-\frac{10}{3}=\frac{7}{15}.\frac{3}{5}\) \(g,x+\frac{3}{22}=\frac{27}{121}.\frac{11}{9}\)
\(h,1-x=\frac{49}{65}.\frac{5}{7}\) \(i,\frac{8}{23}.\frac{46}{24}-x=\frac{1}{3}\) \(k,\frac{62}{7}.x=\frac{29}{9}:\frac{3}{56}\)
1) Tính nhanh:
P1frac{1}{3}cdot1frac{1}{8}cdot1frac{1}{15}cdot1frac{1}{24}cdot1frac{1}{35}cdot1frac{1}{48}cdot1frac{1}{63}cdot1frac{1}{80}
2) So sánh:
Afrac{100^{10}+1}{100^{10}-1} và Bfrac{100^{10}-1}{100^{10}-3}
3) So sánh A và B biết:
Afrac{1}{1cdot2}+frac{1}{2cdot3}+frac{1}{3cdot4}+...+frac{1}{49cdot50}
Bfrac{1}{10}+frac{1}{11}+frac{1}{12}+...+frac{1}{99}+frac{1}{100}
Đọc tiếp
1) Tính nhanh:
P=\(1\frac{1}{3}\cdot1\frac{1}{8}\cdot1\frac{1}{15}\cdot1\frac{1}{24}\cdot1\frac{1}{35}\cdot1\frac{1}{48}\cdot1\frac{1}{63}\cdot1\frac{1}{80}\)
2) So sánh:
A=\(\frac{100^{10}+1}{100^{10}-1}\) và B=\(\frac{100^{10}-1}{100^{10}-3}\)
3) So sánh A và B biết:
A=\(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+...+\frac{1}{49\cdot50}\)
B=\(\frac{1}{10}+\frac{1}{11}+\frac{1}{12}+...+\frac{1}{99}+\frac{1}{100}\)
Bài 1:
\(\frac{32}{15}:\left(-1\frac{1}{5}+1\frac{1}{3}\right)\) \(1\frac{13}{15}.0,75-\left(\frac{8}{15}+0.25\right).\frac{24}{47}\)
\(0,2.\frac{15}{36}-\left(\frac{2}{5}+\frac{2}{3}\right):1\frac{1}{5}\) \(5:\left(4\frac{25}{28}-1\frac{25}{28}\right)-1\frac{3}{8}:\left(\frac{3}{8}+\frac{9}{20}\right)\)
Tính
`S = 3 + 3^2 + 3^3 + ... + 3^99`
`A = \frac{1}{3} + \frac{1}{3^2} + ... + \frac{1}{3^{99}}`
a,frac{2}{3}x-frac{1}{2}frac{1}{10} ;b,5frac{4}{7}:x13 ;c,left(2frac{4}{5}x-50right):frac{2}{3}51
d,frac{2}{3}+frac{1}{3}:xfrac{3}{5} ;e,8frac{2}{3}:x-10-8
g,x+30%x-1,3 ;i,3frac{1}{3}x+16frac{3}{4}-13,25
k,left(2frac{4}{5}x-50right):frac{2}{3}51 ;m,/2x-1/left(-4^2right)
Đọc tiếp
\(a,\frac{2}{3}x-\frac{1}{2}=\frac{1}{10}\) ;\(b,5\frac{4}{7}:x=13\) ;\(c,\left(2\frac{4}{5}x-50\right):\frac{2}{3}=51\)
\(d,\frac{2}{3}+\frac{1}{3}:x=\frac{3}{5}\) ;\(e,8\frac{2}{3}:x-10=-8\)
\(g,x+30\%x=-1,3\) ;\(i,3\frac{1}{3}x+16\frac{3}{4}=-13,25\)
\(k,\left(2\frac{4}{5}x-50\right):\frac{2}{3}=51\) ;m,/2x-1/=\(\left(-4^2\right)\)
1. thực hiện phép tính
a) frac{-1}{2}-frac{9}{8}:0,75 b)frac{4}{3}.frac{11}{15}+frac{4}{15}.frac{4}{3}-2frac{1}{3} c)frac{6}{8}+frac{6}{56}+frac{6}{140}+.....+frac{6}{416}
2. tìm x
a) x ∈ Z, x∈ Ư (4) và x ∠1 b)x - frac{2}{3}20 % c) (2frac{1}{6}-x):frac{2}{3}left(-frac{1}{2}right)^2
Đọc tiếp
1. thực hiện phép tính
a) \(\frac{-1}{2}-\frac{9}{8}:0,75\) b)\(\frac{4}{3}.\frac{11}{15}+\frac{4}{15}.\frac{4}{3}-2\frac{1}{3}\) c)\(\frac{6}{8}+\frac{6}{56}+\frac{6}{140}+.....+\frac{6}{416}\)
2. tìm x
a) x ∈ Z, x∈ Ư (4) và x ∠1 b)x - \(\frac{2}{3}\)=20 % c) \((2\frac{1}{6}-x):\frac{2}{3}=\left(-\frac{1}{2}\right)^2\)