\(\dfrac{3}{4}\) bằng :
a.\(\dfrac{9}{20}\) b.\(\dfrac{12}{16}\) c.\(\dfrac{6}{8}\) d.\(\dfrac{12}{24}\)
chọn câu b hay c hả các pác ?
Điền số thích hợp vào ô vuông:
a) \(\dfrac{1}{2}\)=\(\dfrac{ }{12}\) b)\(\dfrac{ }{8}\)=\(\dfrac{-28}{32}\) c)\(\dfrac{3}{4}\)=\(\dfrac{ }{20}\)
d)\(\dfrac{ }{9}\)=\(\dfrac{-16}{36}\) e)\(\dfrac{3}{4}\)=\(\dfrac{15}{ }\)
a) \(\dfrac{1}{2}\)=\(\dfrac{6}{12}\) b) \(\dfrac{-7}{8}\)=\(\dfrac{-28}{32}\) c)\(\dfrac{3}{4}\)=\(\dfrac{15}{20}\) d) \(\dfrac{-4}{9}\)=\(\dfrac{-16}{36}\)
e) \(\dfrac{3}{4}\)=\(\dfrac{15}{20}\)
HỌC TỐT
a) \(\dfrac{-21}{15}\).\(\dfrac{-10}{14}\) b)\(\left(-\dfrac{2}{3}\right)^2\) c)\(\dfrac{-3}{4}\).\(\dfrac{-4}{5}\).\(\dfrac{16}{9}\) d)\(\dfrac{-8}{3}\).\(\dfrac{5}{6}\) e)\(\dfrac{16}{30}\).\(\dfrac{5}{12}\) f) \(\dfrac{13}{30}\).\(\dfrac{-1}{5}\) g)\(\dfrac{2}{21}\).\(\dfrac{3}{28}\) h)\(\left(\dfrac{-3}{4}\right)^3\)
`a, -21/15 . (-10)/14 = 210/210=1`
`b, (-2/3)^2= 4/9`
`c, (-3)/4 . (-4)/5 . 16/9= 192/180=16/15`
`d, (-8)/3 . 5/6= -40/18=-20/9`
`e, 16/30 . 5/12= 8/15 . 5/12=40/180=2/9`
`f, 13/30 . (-1)/5= -13/150`
`g, 2/21 . 3/28= 6/588= 1/98`
`h, (-3/4)^3= -27/64`
bài 1 quy đồng mẫu các phân số
a,\(\dfrac{3}{8}và\dfrac{5}{12}\)
b,\(\dfrac{-2}{9}và\dfrac{5}{-12}\)
c,\(\dfrac{-3}{16};\dfrac{5}{-24};\dfrac{-21}{56}\)
d,\(\dfrac{17}{60};\dfrac{5}{18};\dfrac{64}{90}\)
a: 3/8=36/96
5/12=40/96
b: -2/9=-24/108
-5/12=-45/108
c: -3/16=-63/336
-5/24=-70/336
-21/56=-126/336
C1: Tính
a,\(\dfrac{7}{8}+\dfrac{10}{16}\)
b,\(\dfrac{12}{4}+\dfrac{6}{5}\)
c,\(\dfrac{23}{9}x\dfrac{4}{7}\)
d,\(\dfrac{8}{9}:\dfrac{6}{4}\)
\(\dfrac{14+10}{16}=\dfrac{24}{16}\)
\(\dfrac{60+24}{20}=\dfrac{84}{20}\)
\(\dfrac{92}{63}\)
\(\dfrac{32}{54}\)
trong các phân số sau, phân số bé nhất là:
A.\(\dfrac{6}{6}\) B.\(\dfrac{6}{7}\) C.\(\dfrac{6}{8}\) D.\(\dfrac{6}{9}\)
Phân số \(\dfrac{5}{6}\) bằng phân số nào dưới đây?
A.\(\dfrac{20}{24}\) B.\(\dfrac{24}{20}\) C.\(\dfrac{20}{18}\) D.\(\dfrac{18}{20}\)
Bài 1: Khoanh vào chữ đặt trước câu trả lời đúng:
a) Phân số dưới đây bằng \(\dfrac{4}{7}\) là:
A. \(\dfrac{12}{25}\) B. \(\dfrac{20}{35}\) C. \(\dfrac{8}{11}\) D. \(\dfrac{16}{21}\)
b) Phân số dưới đây lớn hơn 1 là:
A. \(\dfrac{10}{11}\) B. \(\dfrac{12}{11}\) C. \(\dfrac{15}{15}\) D. \(\dfrac{7}{8}\)
Bài 1: Thực hiện phép tính:
a, \(\left(\dfrac{7}{20}+\dfrac{11}{15}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right)\)
b, \(\dfrac{5-\dfrac{5}{3}+\dfrac{5}{9}-\dfrac{5}{27}}{8-\dfrac{8}{3}+\dfrac{8}{9}-\dfrac{8}{27}}:\dfrac{15-\dfrac{15}{11}+\dfrac{15}{121}}{16-\dfrac{16}{11}+\dfrac{16}{121}}\)
c, \(\dfrac{\dfrac{1}{9}-\dfrac{5}{6}-4}{\dfrac{7}{12}-\dfrac{1}{36}-10}\)
\(a,\left(\dfrac{7}{20}+\dfrac{11}{15}-\dfrac{15}{12}\right):\left(\dfrac{11}{20}-\dfrac{26}{45}\right).\)
\(=\left(\dfrac{21}{60}+\dfrac{44}{60}-\dfrac{75}{60}\right):\left(\dfrac{99}{180}-\dfrac{104}{180}\right).\)
\(=\left(\dfrac{65}{60}-\dfrac{75}{60}\right):\left(-\dfrac{5}{180}\right).\)
\(=-\dfrac{10}{60}:\left(-\dfrac{5}{180}\right).\)
\(=-\dfrac{1}{6}:\left(-\dfrac{1}{36}\right).\)
\(=-\dfrac{1}{6}.\left(-36\right).\)
\(=\dfrac{-1.\left(-36\right)}{6}=\dfrac{36}{6}=6.\)
Vậy......
\(b,\dfrac{5-\dfrac{5}{3}+\dfrac{5}{9}-\dfrac{5}{27}}{8-\dfrac{8}{3}+\dfrac{8}{9}-\dfrac{8}{27}}:\dfrac{15-\dfrac{15}{11}+\dfrac{15}{121}}{16-\dfrac{16}{11}+\dfrac{16}{121}}.\)
\(=\dfrac{5\left(1-\dfrac{1}{3}+\dfrac{1}{9}-\dfrac{1}{27}\right)}{8\left(1-\dfrac{1}{3}+\dfrac{1}{9}-\dfrac{1}{27}\right)}:\dfrac{15\left(1-\dfrac{1}{11}+\dfrac{1}{121}\right)}{16\left(1-\dfrac{1}{11}+\dfrac{1}{121}\right)}.\)
\(=\dfrac{5}{8}:\dfrac{15}{16}.\)
\(=\dfrac{5}{8}.\dfrac{16}{15}=\dfrac{5.16}{8.15}=\dfrac{1.2}{1.3}=\dfrac{2}{3}.\)
Vậy......
c, (làm tương tự câu b).
~ Học tốt!!! ~
Tìm các số nguyên x,y biết:
a)\(\dfrac{6}{2x+1}=\dfrac{2}{7}\)
b) \(\dfrac{24}{7x-3}=\dfrac{-4}{25}\)
c) \(\dfrac{4}{x-6}=\dfrac{y}{24}=\dfrac{-12}{18}\)
d) \(\dfrac{-1}{5}\le\dfrac{x}{8}\le\dfrac{1}{4}\)
e) \(\dfrac{x+46}{20}=x\dfrac{2}{5}\)
f) \(y\dfrac{5}{y}=\dfrac{86}{y}\) ( \(x\dfrac{2}{5};y\dfrac{5}{y}\) là các hỗn số)
a,\(\dfrac{6}{2x+1}=\dfrac{2}{7}\)
⇒\(\dfrac{6}{2x+1}=\dfrac{6}{21}\)
⇒\(2x+1=21\)
\(2x=21-1\)
\(2x=20\)
⇒\(x=10\)
Phân số \(\dfrac{4}{9}\)bằng phân số nào dưới đây:
a. \(\dfrac{8}{27}\)
b. \(\dfrac{16}{27}\)
c. \(\dfrac{12}{18}\)
d. \(\dfrac{12}{27}\)