rút gọn và so sánh
20/35 và 3/7
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a)
\(\dfrac{6}{12}=\dfrac{6:6}{12:6}=\dfrac{1}{2}\)
\(\Rightarrow\dfrac{1}{2}=\dfrac{1\times2}{2\times2}=\dfrac{2}{4}\)
Mà \(\dfrac{2}{4}< \dfrac{3}{4}\)
Vậy \(\dfrac{6}{12}< \dfrac{3}{4}\).
b)
\(\dfrac{8}{10}=\dfrac{8:2}{10:2}=\dfrac{4}{5}\)
Mà \(\dfrac{2}{5}< \dfrac{4}{5}\)
Vậy \(\dfrac{2}{5}< \dfrac{8}{10}\).
c)
\(\dfrac{40}{35}=\dfrac{40:5}{35:5}=\dfrac{8}{7}\)
Mà \(\dfrac{8}{7}>\dfrac{6}{7}\)
Vậy \(\dfrac{40}{35}>\dfrac{6}{7}\).
d)
\(\dfrac{8}{16}=\dfrac{8:8}{16:8}=\dfrac{1}{2}\)
Mà \(\dfrac{1}{2}< \dfrac{5}{2}\)
Vậy \(\dfrac{8}{16}< \dfrac{5}{2}\).
10/15= 10:5/15:5=2/3
7/35= 7:7/35:7= 1/3
Ta thấy: 2/3 > 1/3 (2 > 1)
Hay: 10/15 > 7/35
\(\frac{7}{35}\)= \(\frac{1}{5}\)\(\frac{10}{15}=\frac{2}{3}\)
\(\frac{2}{3}>\frac{1}{5}\) t i c k cho mình nha
Bài 1:
a) \(\dfrac{-5}{6}\ne\dfrac{10}{-14}\left(\dfrac{10}{-14}=-\dfrac{5}{7}\right).\)
b) \(\dfrac{-15}{-60}\ne\dfrac{-3}{12}\left(\dfrac{-15}{-60}=\dfrac{1}{4}\right).\)
Bài 2:
a) \(\dfrac{20}{-140}=-\dfrac{1}{7}.\)
b) \(\dfrac{4.18}{9.12}=\dfrac{72}{108}=\dfrac{2}{3}.\)
c) \(\dfrac{17.25-17.3}{2.\left(-15\right)}=\dfrac{17.\left(25-3\right)}{-30}=-\dfrac{17.22}{30}=\dfrac{374}{30}=\dfrac{187}{15}.\)
Bài 3:
a) \(\dfrac{-3}{5}< \dfrac{4}{-7}.\)
b) \(\dfrac{-4}{21}>\dfrac{-7}{35}.\)
c) \(\dfrac{-7}{24}>\dfrac{-2}{3}.\)
d) \(\dfrac{-52}{167}< \dfrac{-3}{-4}.\)
\(\dfrac{90}{126}=\dfrac{5}{7}\)
\(\Rightarrow\dfrac{90}{126}< \dfrac{6}{7}\) (Vì \(\dfrac{5}{7}< \dfrac{6}{7}\))
\(\dfrac{35}{49}=\dfrac{5}{7}\)
\(\Rightarrow\dfrac{90}{126}=\dfrac{35}{49}\) (Vì \(\dfrac{5}{7}=\dfrac{5}{7}\))
a.Ta có:
\(\dfrac{14}{18}=\dfrac{7}{9}=\dfrac{7\times5}{9\times5}=\dfrac{35}{45}\)
\(\dfrac{21}{35}=\dfrac{3}{5}=\dfrac{3\times9}{5\times9}=\dfrac{27}{45}\)
\(\Rightarrow\dfrac{14}{18}>\dfrac{21}{35}\)
14/8 = 35/45 , 21/35 = 27/45
nên 14/18>21/35
(HT)
Bài 1:
\(\frac{90}{126}=\frac{5}{7};\frac{6}{7}=\frac{6}{7}\)
\(\frac{90}{126}=\frac{5}{7};\frac{35}{49}=\frac{5}{7}\)
Bài 2:
ta có: 8/9 = 0,8888
19/20 = 0,95
10/11 = 0,9090
21/22 = 0,9595
=> 21/22 là phân số lớn nhất
\(\frac{16}{48}=\frac{16:16}{48:16}=\frac{1}{3}\);\(\frac{14}{35}=\frac{14:7}{35:7}=\frac{2}{5}\)
\(\frac{1}{3}=\frac{1\cdot5}{3\cdot5}=\frac{5}{15}\); \(\frac{2}{5}=\frac{2\cdot3}{5\cdot3}=\frac{6}{15}\)
20/35 rút gọn thành 4/7>3/7
=>20/35>3/7 nhé
\(\dfrac{4}{7}>\dfrac{3}{7}\)