bài 1;
3/5 + 4/15
5/6 : -7/12
-21/24 : -14/8
4/5 : -8/15
5/12 - -7/6
-15/16 . 8/25
bài 2 tính nhanh
6 bốnphần 5 - ( 1 hai phần ba + 3 bốn phần năm )
6 năm phần bảy trừ ( 1 ba phần bốn cộng hai năm phần bảy)
4/19 . -3/7 + -3/7 . 15/19 + 5/7
5/9 . 7/13 + 5/9 . 9/13 - 5/9 . 3/13
BÀI 3 TÌM X BIẾT
x/5 = 2/3
x/3 - 1/2 = 1/5
4/5 + x = 2/3
3/4 - x = 1/3
x - 5/9 = -2/3
1/2x + 1/2 = 5/2
-2/3 - 1/3 ( 2x-5) = 3/2
ba 1 phần 3 + 5/6 x = 3 hai phần 1
3/8 - 1/6 x = 1/4
BÀI 4 : SO SÁNH
2/3 và 1/4
7/10 và 7/8
14/21 và 60/72
11/45 và 22/37
BÀI 5 XEEPS CÁC PHÂN SỐ SAU THEO THỨ TỰ TĂNG DẦN
A. 9/19;-25/19;20/19;42/19;-13/19
B. 1/3;1/5; -2/-5; -1/10;4/15
BÀI 6; TÍNH TỔNG CÁC SỐ SAU
A= 7/10.11+ 7/11.12 +7/12.13+...+7/69.70
B= 1/25.27+1/27.29+ 1/ 29. 31+...+1/73.75
A=2 mủ 0 + 2 mủ 1 +2 mủ 2+ ....+2 mú2010
B= 1+3+3+2 mú 2+......3 mú 100
Bài 1:
\(\frac{3}{5}+\frac{4}{15}=\frac{9}{15}+\frac{4}{15}=\frac{13}{15}\)
\(\frac{5}{6}:\frac{-7}{12}=\frac{5}{6}.\frac{-12}{7}=\frac{-60}{42}=\frac{-10}{7}\)
\(\frac{-21}{24}:\frac{-14}{8}=\frac{-21}{24}.\frac{-8}{14}=\frac{168}{336}=\frac{1}{2}\)
\(\frac{4}{5}:\frac{-8}{15}=\frac{4}{5}.\frac{-15}{8}=\frac{-60}{40}=\frac{-3}{2}\)
\(\frac{5}{12}-\frac{-7}{6}=\frac{5}{12}+\frac{7}{6}=\frac{5}{12}+\frac{14}{12}=\frac{19}{12}\)
\(\frac{-15}{16}.\frac{8}{25}=\frac{-120}{400}=\frac{-3}{10}\)
Bài 2 :
\(6\frac{4}{5}-\left(1\frac{2}{3}+3\frac{4}{5}\right)\)
\(=\frac{34}{5}-\left(\frac{5}{3}+\frac{19}{5}\right)\)
\(=\frac{34}{5}-\frac{5}{3}-\frac{19}{5}\)
\(=\left(\frac{34}{5}-\frac{19}{5}\right)-\frac{5}{3}\)
\(=3-\frac{5}{3}\)
\(=\frac{4}{3}\)
\(6\frac{5}{7}-\left(1\frac{2}{3}+2\frac{5}{7}\right)\)
\(=\frac{47}{7}-\left(\frac{5}{3}+\frac{19}{7}\right)\)
\(=\frac{47}{7}-\frac{5}{3}-\frac{19}{7}\)
\(=\left(\frac{47}{7}-\frac{19}{7}\right)-\frac{5}{3}\)
\(=4-\frac{5}{3}\)
\(=\frac{7}{3}\)
\(\frac{4}{19}.\frac{-3}{7}+\frac{-3}{7}.\frac{15}{19}+\frac{5}{7}\)
\(=\left(\frac{4}{19}+\frac{15}{19}\right).\frac{-3}{7}+\frac{5}{7}\)
\(=1.\frac{-3}{7}+\frac{5}{7}\)
\(=\frac{-3}{7}+\frac{5}{7}\)
\(=\frac{2}{7}\)
\(\frac{5}{9}.\frac{7}{13}+\frac{5}{9}.\frac{9}{13}-\frac{5}{9}.\frac{3}{13}\)
\(=\frac{5}{9}.\left(\frac{7}{13}+\frac{9}{13}-\frac{3}{13}\right)\)
\(=\frac{5}{9}.1\)
\(=\frac{5}{9}\)
Bài 3 :
\(\frac{x}{5}=\frac{2}{3}\)
\(\Rightarrow x.3=5.2\)
\(\Rightarrow x.3=10\)
\(\Rightarrow x=\frac{10}{3}\)
\(\frac{x}{3}-\frac{1}{2}=\frac{1}{5}\)
\(\frac{x}{3}=\frac{1}{5}+\frac{1}{2}\)
\(\frac{x}{3}=\frac{7}{10}\)
\(\Rightarrow x.10=3.7\)
\(\Rightarrow x.10=21\)
\(\Rightarrow x=\frac{21}{10}\)
\(\frac{4}{5}+x=\frac{2}{3}\)
\(x=\frac{2}{3}-\frac{4}{5}\)
\(x=\frac{-2}{15}\)
\(\frac{3}{4}-x=\frac{1}{3}\)
\(x=\frac{3}{4}-\frac{1}{3}\)
\(x=\frac{5}{12}\)
\(x-\frac{5}{9}=\frac{-2}{3}\)
\(x=\frac{-2}{3}+\frac{5}{9}\)
\(x=\frac{-1}{9}\)
\(\frac{1}{2}x+\frac{1}{2}=\frac{5}{2}\)
\(\frac{1}{2}x=\frac{5}{2}-\frac{1}{2}\)
\(\frac{1}{2}x=2\)
\(x=2:\frac{1}{2}\)
\(x=4\)
\(\frac{-2}{3}-\frac{1}{3}.\left(2x-5\right)=\frac{3}{2}\)
\(\frac{1}{3}.\left(2x-5\right)=\frac{-2}{3}-\frac{3}{2}\)
\(\frac{1}{3}.\left(2x-5\right)=\frac{-19}{10}\)
\(2x-5=\frac{-19}{10}:\frac{1}{3}\)
\(2x-5=\frac{-57}{10}\)
\(2x=\frac{-57}{10}+5\)
\(2x=\frac{-7}{10}\)
\(x=\frac{-7}{10}:2\)
\(x=\frac{-7}{20}\)
\(3\frac{1}{3}+\frac{5}{6}x=3\frac{2}{1}\)
\(\frac{10}{3}+\frac{5}{6}x=5\)
\(\frac{5}{6}x=5-\frac{10}{3}\)
\(\frac{5}{6}x=\frac{5}{3}\)
\(x=\frac{5}{3}:\frac{5}{6}\)
\(x=2\)
\(\frac{3}{8}-\frac{1}{6}x=\frac{1}{4}\)
\(\frac{1}{6}x=\frac{3}{8}-\frac{1}{4}\)
\(\frac{1}{6}x=\frac{1}{8}\)
\(x=\frac{1}{8}:\frac{1}{6}\)
\(x=\frac{3}{4}\)
Bài 4 :
Ta có :\(\frac{2}{3}=\frac{2.4}{3.4}=\frac{8}{12};\frac{1}{4}=\frac{1.3}{4.3}=\frac{3}{12}\)
Vì 8 > 3 nên \(\frac{8}{12}>\frac{3}{12}\)hay \(\frac{2}{3}>\frac{1}{4}\)
Ta có : 10 > 8 nên \(\frac{7}{10}< \frac{7}{8}\)
Ta có : \(\frac{14}{21}=\frac{14.24}{21.24}=\frac{336}{504};\frac{60}{72}=\frac{60.7}{72.7}=\frac{420}{504}\)
Vì 336 < 420 nên \(\frac{336}{504}< \frac{420}{504}\)hay \(\frac{14}{21}< \frac{60}{72}\)
Ta có : \(\frac{11}{45}=\frac{11.37}{45.37}=\frac{407}{1665};\frac{22}{37}=\frac{22.45}{45.37}=\frac{990}{1665}\)
Vì 407 < 990 nên \(\frac{407}{1665}< \frac{990}{1665}\)hay \(\frac{11}{45}< \frac{22}{37}\)
Bài 1
a.61/60
b.4/35
c.-10/7
d.1/ hai
e.3/- hai
f.-hai3/hai muoi
g.19/1hai
h.-3/10
Bài hai.
a.4/3
b.9/4
c.5/4
d.11/7
e.-6/5
f-hai/3
g.hai/7
h.5/9
Bài 3.
a.10/3
b.hai1/10
c.hai/3
d.5/1hai
e.-1/9
f.4
g.
h.3/4
i.1/5
bài5
A. -hai5/19 ; -13/19 ; 9/19 ; 14/19 ;hai0/19 ; 30/19 ; 4hai/19
