tính:
a).2/5+3/6 b).5/9-1/6. c).3/4x7/9. d).15/18:9/36
bài 2:tính
a).3/4x7/6+1/3. b).5/3x9/15-1/5. c).1/4x1/5:1/3. d).7/9:14/15x1/2
ai làm đầy đủ phép tính của từng bài mik tick.nói luôn ra đáp án mik ko tick
K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Những câu hỏi liên quan
8 tháng 3 2017
a=3/4*7/6=1/2+1/3=5/6
b=5/3*9/15=1-1/5=4/5
c=1/4*1/5=1/20:1/3=3/20
d=7/9:14/15=5/6*1/2=5/12
S
9 tháng 3 2017
a) \(\frac{2}{5}+\frac{3}{6}=\frac{12}{30}+\frac{15}{30}\)
\(=\frac{12+15}{30}\)
\(=\frac{27}{30}=\frac{9}{10}\)
b) \(\frac{5}{9}-\frac{1}{6}=\frac{30}{54}-\frac{9}{54}\)
\(=\frac{30-9}{54}\)
\(=\frac{21}{54}=\frac{7}{18}\)
c) \(\frac{3}{4}\times\frac{7}{9}=\frac{3\times7}{4\times9}\)
\(=\frac{27}{36}=\frac{3}{4}\)
d) \(\frac{15}{18}:\frac{3}{36}=\frac{15}{18}\times\frac{36}{3}\)
\(=\frac{15\times36}{18\times3}\)
\(=\frac{540}{54}=10\)
Vậy a) 9/10 b) 7/18 c) 3/4 ; d) 10
ủng hộ nha
9 tháng 3 2017
a) 2/5+3/6
= 12/30+15/30
=27/30=9/10
b)5/9-1/6
=10/18-3/18
=7/18
c)3/4*7/9
=21/36=7/12
d)15/18:/36
=10/3
27 tháng 7 2021
a) Ta có: \(\dfrac{-5}{7}\left(\dfrac{14}{5}-\dfrac{7}{10}\right):\left|-\dfrac{2}{3}\right|-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)+\dfrac{10}{3}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\)
\(=\dfrac{-5}{7}\cdot\dfrac{3}{2}\cdot\dfrac{21}{10}-\dfrac{3}{4}\cdot\dfrac{56}{3}+\dfrac{10}{3}\cdot\dfrac{8}{15}\)
\(=\dfrac{-9}{4}-14+\dfrac{16}{9}\)
\(=\dfrac{-1621}{126}\)
b) Ta có: \(\dfrac{17}{-26}\cdot\left(\dfrac{1}{6}-\dfrac{5}{3}\right):\dfrac{17}{13}-\dfrac{20}{3}\left(\dfrac{2}{5}-\dfrac{1}{4}\right)+\dfrac{2}{3}\left(\dfrac{6}{5}-\dfrac{9}{2}\right)\)
\(=\dfrac{-17}{26}\cdot\dfrac{13}{17}\cdot\dfrac{-3}{2}-\dfrac{20}{3}\cdot\dfrac{3}{20}+\dfrac{2}{3}\cdot\dfrac{-33}{10}\)
\(=\dfrac{3}{4}-1-\dfrac{11}{5}\)
\(=-\dfrac{49}{20}\)
VT
20 tháng 8 2017
\(a,=\frac{7-1}{1.3.7}+\frac{9-3}{3.7.9}+\frac{13-7}{7.9.13}+\frac{15-9}{9.13.15}\)\(+\frac{19-13}{13.15.19}\)
\(=\frac{1}{1.3}-\frac{1}{3.7}+\frac{1}{3.7}-\frac{1}{7.9}+\frac{1}{7.9}-\frac{1}{9.13}+\frac{1}{9.13}-\frac{1}{13.15}+\frac{1}{13.15}-\frac{1}{15.19}\)
\(=\frac{1}{1.3}-\frac{1}{15.19}=\frac{95}{285}-\frac{1}{285}=\frac{94}{285}\)
\(b,=\frac{1}{6}.\left(\frac{6}{1.3.7}+\frac{6}{3.7.9}+\frac{6}{7.9.13}+\frac{6}{9.13.15}+\frac{6}{13.15.19}\right)\)
làm giống như trên
\(c,=\frac{1}{8}.\left(\frac{1}{1.2.3}+\frac{1}{2.3.4}+\frac{1}{3.4.5}+...+\frac{1}{48.49.50}\right)\)
\(=\frac{1}{16}.\left(\frac{2}{1.2.3}+\frac{2}{2.3.4}+\frac{2}{3.4.5}+...+\frac{2}{48.49.50}\right)\)
\(=\frac{1}{16}.\left(\frac{3-1}{1.2.3}+\frac{4-2}{2.3.4}+\frac{5-3}{3.4.5}+...+\frac{50-48}{48.49.50}\right)\)
\(=\frac{1}{16}.\left(\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+\frac{1}{3.4}-\frac{1}{4.5}+...+\frac{1}{48.49}-\frac{1}{49.50}\right)\)
\(=\frac{1}{16}.\left(\frac{1}{2}-\frac{1}{2450}\right)=\frac{1}{16}.\left(\frac{1225}{2450}-\frac{1}{2450}\right)=\frac{153}{4900}\)
\(d,=\frac{5}{7}.\left(\frac{7}{1.5.8}+\frac{7}{5.8.12}+\frac{7}{8.12.15}+...+\frac{7}{33.36.40}\right)\)
\(=\frac{5}{7}.\left(\frac{8-1}{1.5.8}+\frac{12-5}{5.8.12}+\frac{15-8}{8.12.15}+...+\frac{40-33}{33.36.40}\right)\)
\(=\frac{5}{7}.\left(\frac{1}{1.5}-\frac{1}{5.8}+\frac{1}{5.8}-\frac{1}{8.12}+\frac{1}{8.12}-\frac{1}{12.15}+...+\frac{1}{33.36}-\frac{1}{36.40}\right)\)
\(=\frac{5}{7}.\left(\frac{1}{5}-\frac{1}{1440}\right)=\frac{5}{7}.\left(\frac{288}{1440}-\frac{1}{1440}\right)=\frac{41}{288}\)
P/S: . là nhân nha
8 tháng 3 2017
Tính
a ) 5/2 x 1/3 + 1/4
= 5/5+1/4
=13/12
b)5/2 + 1/3 x 1/4
= 5/2 + 1/12
= 31/12
c ) 5/2 -1/3 :1/4
= 5/2 - 4/3
= 7/6
tk mk nha ( nếu đúng )
hihi mơn nha !!!!!!!!!!
8 tháng 3 2017
a. = (5/2x2/3) +1/4
= 5/3+1/4= 23/12
b. = 5/2+( 1/3x1/4)
= 5/2+1/12
=31/12
c. =5/2-( 1/3:1/4)
= 5/2-4/3
= 7/6
14 tháng 4 2023
a: =35/17-18/17-9/5+4/5
=1-1=0
b: =-7/19(3/17+8/11-1)
=7/19*18/187=126/3553
c: =26/15-11/15-17/3-6/13
=1-6/13-17/3
=7/13-17/3=-200/39
Bài 1
a 2/5+3/6=12/30+15/30=27/30=9/10 .
b 5/9-1/6=30/54-9/54=21/54=7/18