\(7\dfrac{4}{5}và9\dfrac{1}{2}\\ Tacó:7< 9\\ \Rightarrow7\dfrac{4}{5}< 9\dfrac{1}{2}\\ 7\dfrac{1}{6}và3\dfrac{4}{5}\\ Tacó:7>3\\ \Rightarrow7\dfrac{1}{6}>3\dfrac{4}{5}\)

Câu cuối không phải hỗn số

1: B là số nguyên

=>n-3 thuộc {1;-1;5;-5}

=>n thuộc {4;2;8;-2}

3:

a: -72/90=-4/5
b: 25*11/22*35

\(=\dfrac{25}{35}\cdot\dfrac{11}{22}=\dfrac{5}{7}\cdot\dfrac{1}{2}=\dfrac{5}{14}\)

c: \(\dfrac{6\cdot9-2\cdot17}{63\cdot3-119}=\dfrac{54-34}{189-119}=\dfrac{20}{70}=\dfrac{2}{7}\)

quy đồng ik

cho về cùng mẫu

\(2\dfrac{3}{4}=\dfrac{2\times4+3}{4}=\dfrac{11}{4}\\ 3\dfrac{4}{5}=\dfrac{3\times5+4}{5}=\dfrac{19}{5}\\ 4\dfrac{3}{5}=\dfrac{4\times5+3}{5}=\dfrac{23}{5}\\ 11\dfrac{12}{13}=\dfrac{11\times13+12}{13}=\dfrac{155}{13}\\ 12\dfrac{11}{13}=\dfrac{12\times13+11}{13}=\dfrac{167}{13}\\ 3\dfrac{3}{5}=\dfrac{3\times5+3}{5}=\dfrac{18}{5}\)

2\(\dfrac{3}{4}\)=\(\dfrac{11}{4}\)

3\(\dfrac{4}{5}\)=\(\dfrac{19}{5}\)

4\(\dfrac{3}{5}\)=\(\dfrac{23}{5}\)

11\(\dfrac{12}{13}\)=\(\dfrac{155}{13}\)

12\(\dfrac{11}{13}\)=\(\dfrac{167}{13}\)

3\(\dfrac{3}{5}\)=\(\dfrac{18}{5}\).

a: \(\dfrac{-7}{6}=\dfrac{-7\cdot3}{6\cdot3}=\dfrac{-21}{18}\)

\(\dfrac{-11}{9}=\dfrac{-11\cdot2}{9\cdot2}=\dfrac{-22}{18}\)

mà -21>-22

nên \(-\dfrac{7}{6}>-\dfrac{11}{9}\)

b: \(\dfrac{5}{-7}=\dfrac{-5}{7}=\dfrac{-5\cdot5}{7\cdot5}=\dfrac{-25}{35}\)

\(\dfrac{-4}{5}=\dfrac{-4\cdot7}{5\cdot7}=\dfrac{-28}{35}\)

mà -25>-28

nên \(\dfrac{5}{-7}>\dfrac{-4}{5}\)

c: \(\dfrac{-8}{7}< -1\)

\(-1< -\dfrac{2}{5}\)

Do đó: \(-\dfrac{8}{7}< -\dfrac{2}{5}\)

d: \(-\dfrac{2}{5}< 0\)

\(0< \dfrac{1}{3}\)

Do đó: \(-\dfrac{2}{5}< \dfrac{1}{3}\)

4\(\dfrac{1}{2}\)=4,5      3\(\dfrac{4}{5}\)=3,8         2\(\dfrac{3}{4}\)=2,75      1\(\dfrac{12}{25}\)=1,48.

4 1/2=4,5

3 4/5=3,8

2 3/4=2,75

1 12/25=1,48

đúng 100% nha

Ta có:

\(\dfrac{-49}{211}< 0;\dfrac{13}{1999}>0\)

⇒ \(\dfrac{-49}{211}< \dfrac{13}{1999}\)

-49/211<0<13/1999

Thiếu đề hay xao ý bn

thiếu j bạn, > nhé

a: \(\dfrac{2}{3}+\dfrac{7}{3}=\dfrac{9}{3}\)

\(\dfrac{7}{3}+\dfrac{2}{3}=\dfrac{9}{3}\)

=>\(\dfrac{2}{3}+\dfrac{7}{3}=\dfrac{7}{3}+\dfrac{2}{3}\)

\(\dfrac{3}{5}+\dfrac{4}{5}=\dfrac{7}{5}\)

\(\dfrac{4}{5}+\dfrac{3}{5}=\dfrac{7}{5}\)

=>\(\dfrac{3}{5}+\dfrac{4}{5}=\dfrac{4}{5}+\dfrac{3}{5}\)

b: \(\dfrac{7}{9}+\dfrac{16}{9}=\dfrac{7+16}{9}=\dfrac{23}{9}\)

\(\dfrac{16}{9}+\dfrac{7}{9}=\dfrac{16+7}{9}=\dfrac{23}{9}\)

Do đó: \(\dfrac{7}{9}+\dfrac{16}{9}=\dfrac{16}{9}+\dfrac{7}{9}\)