Tính:
a ) − 5 6 : 2 7 b ) − 4 7 : − 1 3 ; c ) − 10 : 2 3 d ) 3 5 : ( − 5 )
6 tính: a) 4/5+1/5:2/5= b) 5/6:5 nhân 2/5
a: \(=\dfrac{4}{5}+\dfrac{1}{5}\cdot\dfrac{5}{2}=\dfrac{4}{5}+\dfrac{1}{2}=\dfrac{8}{10}+\dfrac{5}{10}=\dfrac{13}{10}\)
b: \(=\dfrac{5}{6}\cdot\dfrac{1}{5}\cdot\dfrac{2}{5}=\dfrac{1}{6}\cdot\dfrac{2}{5}=\dfrac{2}{30}=\dfrac{1}{15}\)
a) \(=\dfrac{13}{10}\)
b) \(=\dfrac{1}{15}\)
tính A= 5/13+5/12+5/11+5/10 trên 6/13+6/12+6/11+6/10 - 3/4
Đặt tính rồi tính :
\(a.\dfrac{5}{6}+\dfrac{2}{5}\)
\(b.\dfrac{6}{5}-\dfrac{3}{4}\)
\(c.\dfrac{9}{16}\times\dfrac{4}{3}\)
\(d.\dfrac{8}{17}:6\)
a: =25/30+12/30=37/30
b: =24/20-15/20=9/20
c: =36/48=3/4
d: =8/17x1/6=8/102=4/51
a) \(\dfrac{25}{30}+\dfrac{12}{30}=\dfrac{37}{30}\)
b) \(\dfrac{24}{20}-\dfrac{15}{20}=\dfrac{9}{20}\)
c) \(\dfrac{36}{48}=\dfrac{3}{4}\)
d) \(\dfrac{8}{17}\times\dfrac{1}{6}=\dfrac{8}{102}=\dfrac{4}{51}\)
\(\dfrac{5}{6}+\dfrac{2}{5}=\dfrac{25}{30}+\dfrac{12}{30}=\dfrac{37}{30}\)
\(\dfrac{6}{5}-\dfrac{3}{4}=\dfrac{24}{20}-\dfrac{15}{20}=\dfrac{9}{20}\)
\(\dfrac{9}{16}\times\dfrac{4}{3}=\dfrac{36}{48}\)
\(\dfrac{8}{17}:6=\dfrac{8}{102}\)
Tính a) 1/6 + -2/5. b) (-2) + -5/8. c) 6/13 + -14/39 d) 3/5 - 5/6. e) -5/9 - -5/12
a: =5/30-12/30=-7/30
b: =-2-5/8=-16/8-5/8=-21/8
c: =6/13-14/39=18/39-14/39=4/39
d: =18/30-25/30=-7/30
e: =-5/9+5/12=-20/36+15/36=-5/36
a) \(\dfrac{-7}{30}\)
b) \(\dfrac{-21}{8}\)
c) \(\dfrac{-7}{30}\)
d) \(\dfrac{-5}{36}\)
\(a,\dfrac{1}{6}+\dfrac{-2}{5}=\dfrac{5}{30}+\dfrac{-12}{30}=\dfrac{-7}{30}\\ b,\left(-2\right)+\dfrac{-5}{8}=\dfrac{-16}{8}+\dfrac{-5}{8}=\dfrac{-21}{8}\\ c,\dfrac{6}{13}+\dfrac{-14}{39}=\dfrac{18}{39}+\dfrac{-14}{39}=\dfrac{4}{39}\\ d,\dfrac{3}{5}-\dfrac{5}{6}=\dfrac{18}{30}-\dfrac{25}{30}=\dfrac{-7}{30}\\ e,\dfrac{-5}{9}-\dfrac{-5}{12}=\dfrac{-20}{36}-\dfrac{-15}{36}=\dfrac{-5}{36}\)
Tính nhanh
a) 5/1x3 + 5/3x5 + 5/5x7 + ........ + 5/43x45
b) 6/1x4 + 6/4x7 + 6/7x10 + ...... + 6/97x100
\(a,\frac{5}{1.3}+\frac{5}{3.5}+\frac{5}{5.7}+...+\frac{5}{43.45}=\frac{5}{2}\left(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{43.45}\right)=\frac{5}{3}\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{43}-\frac{1}{45}\right)=\frac{5}{3}.\frac{44}{45}=\frac{44}{27}\)
tính giá trị biểu thức sau(tính nhanh nếu có thể)
a)3^3.9-3^4.3+5^8.5^0-5^12:25^2
b)A=(25^6+15^6-10^6):5^6
c)B=9!-8!-7!.8^2
a+5/a-5=b+6/b-6
Tính giá trị của tỉ số a/b
Tính giá trị biểu thức (theo mẫu)
a | 6 x a |
---|---|
5 | 6 x 5 = 30 |
7 | |
10 |
a | 6 x a |
---|---|
5 | 6 x 5 = 30 |
7 | 6 x 7 = 42 |
10 | 6 x 10 = 60 |
1) tính
A) 7/8 - 5/12
B) 8/15 - 2/5
C) 5/6 - 3/10
D) 7/10 - 1/5
2) rút gọn rồi tính
A);5/10 - 2/15
B) 5/20 - 1/6
C) 6/18 - 6/24
D) 5 9 - 3/12
A) \(\frac{7}{8}-\frac{5}{12}=\frac{84}{96}-\frac{40}{96}=\frac{44}{96}=\frac{11}{24}\)
B)\(\frac{8}{15}-\frac{2}{5}=\frac{8}{15}-\frac{6}{15}=\frac{2}{15}\)
C)\(\frac{5}{6}-\frac{3}{10}=\frac{50}{60}-\frac{18}{60}=\frac{32}{60}=\frac{8}{15}\)
D)\(\frac{7}{10}-\frac{1}{5}=\frac{7}{10}-\frac{2}{10}=\frac{5}{10}=\frac{1}{2}\)
2)A)\(\frac{5}{10}-\frac{2}{15}=\frac{1}{2}-\frac{2}{15}=\frac{15}{30}-\frac{4}{30}=\frac{11}{30}\)
B)\(\frac{5}{20}-\frac{1}{6}=\frac{1}{4}-\frac{1}{6}=\frac{6}{24}-\frac{4}{24}=\frac{2}{24}=\frac{1}{12}\)
C)\(\frac{6}{18}-\frac{6}{24}=\frac{1}{3}-\frac{1}{4}=\frac{4}{12}-\frac{3}{12}=\frac{1}{12}\)
D)\(\frac{5}{9}-\frac{3}{12}=\frac{5}{9}-\frac{1}{4}=\frac{20}{36}-\frac{9}{36}=\frac{11}{36}\)
Chúc bạn học tốt
bài 2 thực hiện phép tính ( tính nhanh nếu có thể)
A, 7/11 +5/6 - -4/11 - 1/6
B, 5/9 . 7/13 +5/9 . 9/13 - 5/9 : 13/5
=7/11+5/6+4/11-1/6
=(7/11+4/11)+(5/6-1/6)
=1+2/3
=5/3
\(A,\dfrac{7}{11}+\dfrac{5}{6}-\dfrac{-4}{11}-\dfrac{1}{6}\)
\(= (\dfrac{7}{11}+\dfrac{-4}{11})-(\dfrac{5}{6}-\dfrac{1}{6})\)
\(=\dfrac{3}{11}-\dfrac{2}{3}\)
\(= \dfrac{9}{33}-\dfrac{22}{33}\)
\(= \dfrac{-13}{33}\)
\(B,\dfrac{5}{9}.\dfrac{7}{3}+\dfrac{5}{9}.\dfrac{9}{13}-\dfrac{5}{9}:\dfrac{13}{5}\)
\(=(\dfrac{5}{9}.\dfrac{5}{9}:\dfrac{5}{9}).\dfrac{7}{3}+\dfrac{9}{13}-\dfrac{13}{5}\)
\(=(\dfrac{5}{9}.\dfrac{7}{3})+(\dfrac{9}{13}-\dfrac{13}{5})\)
\(=(\dfrac{5}{9}.\dfrac{21}{9})+(\dfrac{45}{65}-\dfrac{169}{65})\)
\(=\dfrac{35}{27}+\dfrac{-124}{65}\)
\(=\dfrac{2275}{1755}+\dfrac{-3348}{1755}\)
\(=\dfrac{-1073}{1755}\)