Ôn tập
1.Tính
130050:452 19183:78 204 \(\times\) 1942
2.Tính
\(\dfrac{4}{9}+\dfrac{3}{7}\) \(\dfrac{7}{15}-\dfrac{11}{30}\)
2 bạn đầu tiên xong .Mn trình bày rõ ràng cho e ạ cảm ơn!
\(\dfrac{-4}{11}\times\dfrac{7}{15}-\dfrac{4}{15}\times\dfrac{8}{11}+\dfrac{-5}{11}\)
\(2\dfrac{2}{3}-2\dfrac{3}{5}\times\dfrac{10}{7}-\dfrac{7}{5}\)
các bạn làm trong hôm nay dùm mình nhé, cảm ơn
a, \(\dfrac{-4}{11}.\dfrac{7}{15}-\dfrac{4}{15}.\dfrac{8}{11}+\dfrac{-5}{11}\)
=\(\dfrac{-4}{11}.\dfrac{7}{15}+\dfrac{-4.8}{15.11}+\dfrac{-5}{11}\)
=\(\dfrac{-4}{11}.\dfrac{7}{15}+\dfrac{8}{15}.\dfrac{-4}{11}+\dfrac{-5}{11}\)
=\(\dfrac{-4}{11}.\left(\dfrac{7}{15}+\dfrac{8}{15}\right)+\dfrac{-5}{11}\)
=\(\dfrac{-4}{11}.1+\dfrac{-5}{11}\)
=\(\dfrac{-9}{11}\)
giải hộ mik nha , giải rõ ràng , chi tiết cho mik ra nhá
Bài 1 : Tính
a) \(\dfrac{7}{12}+\dfrac{3}{4}\) x \(\dfrac{2}{9}\) b) \(\dfrac{8}{9}-\dfrac{4}{15}\) : \(\dfrac{2}{5}\)
\(a,\dfrac{7}{12}+\dfrac{3}{4}\times\dfrac{2}{9}=\dfrac{7}{12}+\dfrac{1}{6}=\dfrac{7}{12}+\dfrac{2}{12}=\dfrac{9}{12}=\dfrac{3}{4}\)
\(b,\dfrac{8}{9}-\dfrac{4}{15}:\dfrac{2}{5}=\dfrac{8}{9}-\dfrac{4}{15}\times\dfrac{5}{2}=\dfrac{8}{9}-\dfrac{2}{3}=\dfrac{8}{9}-\dfrac{6}{9}=\dfrac{2}{9}\)
Đáp án a là 0,75
Đáp án b: là 0.86222222222
Bài 3 : Tính
a) \(\dfrac{2}{5}+\dfrac{11}{15}\) b) \(\dfrac{2}{7}-\dfrac{2}{11}\) c) \(\dfrac{11}{13}\) x \(\dfrac{26}{31}\) d) \(\dfrac{1}{2}:\dfrac{1}{3}\) x \(\dfrac{2}{5}\)
giúp mik với , giải rõ ràng ra nha . ( đùưng vào nói ltinh gì zới mik nha )
a \(\dfrac{6}{15}+\dfrac{11}{15}=\dfrac{17}{15}\)
b \(\dfrac{22}{77}-\dfrac{14}{77}=\dfrac{8}{77}\)
c \(\dfrac{11}{13}\times\dfrac{26}{31}=11\times\dfrac{2}{31}=\dfrac{22}{31}\)
d \(\dfrac{1}{2}\times3\times\dfrac{2}{5}=\dfrac{3}{5}\)
a, 2/5 + 11/15 = 6/15 + 11/15 = 17/15
b,2/7 - 2/11 = 22/77 - 14/77 = 8/77
c, 11/13 x 26/31= 11 x 2/31 =22/31
d, 1/2 : 1/3 x 2/5
= ( 1/2 x 2/5 ) : 1/3
= 1/5 : 1/3
= 3/5
A = \(\dfrac{-19}{9}\times\dfrac{1}{2}-\dfrac{4}{11}\times\dfrac{-11}{9}+\left(-\dfrac{2}{3}\right)\)
B = \(\left(-\dfrac{15}{6}\right)\div\dfrac{-1}{2}+\dfrac{7}{-12}-\dfrac{1}{3}\times\dfrac{-11}{2}\)
C = \(\dfrac{3}{4}\times\left(-8\right)-\dfrac{1}{3}\times\dfrac{-7}{2}-\dfrac{5}{18}\)
\(A=\dfrac{-19}{9}.\dfrac{1}{2}-\dfrac{4}{11}.\dfrac{-11}{9}+\left(-\dfrac{2}{3}\right)=-\dfrac{23}{18}\)
\(B=\left(-\dfrac{15}{6}\right):\dfrac{-1}{2}+\dfrac{7}{-12}-\dfrac{1}{3}.\dfrac{-11}{2}=\dfrac{25}{4}\)
\(C=\dfrac{3}{4}.\left(-8\right)-\dfrac{1}{3}.\dfrac{-7}{2}-\dfrac{5}{18}=-\dfrac{46}{9}\)
\(A=\dfrac{-19}{18}+\dfrac{4}{9}-\dfrac{2}{3}=\dfrac{-19}{18}+\dfrac{8}{18}-\dfrac{12}{18}=\dfrac{-23}{18}\)
\(B=\dfrac{-5}{2}\cdot\dfrac{-2}{1}-\dfrac{7}{12}+\dfrac{11}{6}=\dfrac{5\cdot12-7+22}{12}=\dfrac{75}{12}=\dfrac{25}{4}\)
tính nhanh cho mn
\(3+\dfrac{4}{9}\times\dfrac{7}{25}\times\dfrac{27}{12}\times3\dfrac{4}{7}-\dfrac{7}{25}\)
\(=3+\dfrac{4}{9}\cdot\dfrac{7}{25}\cdot\dfrac{9}{4}\cdot\dfrac{25}{7}=3+\dfrac{4.7.9.25}{9.25.4.7}=3+1=4\)
\(=3+\dfrac{4}{9}\times\dfrac{7}{25}\times\dfrac{9}{4}\times\dfrac{25}{7}-\dfrac{7}{25}\)
\(=3+\dfrac{4.7.9.45}{9.25.4.7}-\dfrac{7}{25}\)
\(=3+1-\dfrac{7}{25}\)
\(=4-\dfrac{7}{25}\)
\(=\dfrac{93}{25}\)
Tính nhanh: \(\dfrac{-3}{7}.\dfrac{15}{13}-\dfrac{3}{7}.\dfrac{11}{13}-\dfrac{3}{7}\)
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\(-\dfrac{3}{7}\times\dfrac{15}{13}-\dfrac{3}{7}\times\dfrac{11}{13}-\dfrac{3}{7}\)
\(=-\dfrac{3}{7}\left(\dfrac{15}{13}+\dfrac{11}{13}+1\right)\)
\(=-\dfrac{3}{7}\left(\dfrac{15}{13}+\dfrac{11}{13}+\dfrac{13}{13}\right)\)
\(=-\dfrac{3}{7}\times\dfrac{39}{13}=-\dfrac{3}{7}\times3=-\dfrac{9}{7}\)
Tính
a.\(\dfrac{4}{9}+\dfrac{3}{7}\) \(\dfrac{3}{4}+\dfrac{7}{24}\) \(\dfrac{1}{3}+\dfrac{2}{9}+\dfrac{4}{27}\)
b.\(\dfrac{5}{6}-\dfrac{3}{8}\) \(\dfrac{7}{15}-\dfrac{11}{30}\) \(\dfrac{2}{3}+\dfrac{1}{6}-\dfrac{7}{12}\)
c.\(\dfrac{18}{25}\times\dfrac{15}{6}\) \(\dfrac{30}{49}:\dfrac{6}{7}\) \(\dfrac{1}{2}\times\dfrac{3}{4}:\dfrac{6}{5}\)
d.\(8\times\dfrac{3}{5}:\dfrac{12}{5}\) \(4:\dfrac{9}{5}:\dfrac{10}{3}\)
3 bn đầu tiên xong mik sẽ tick
a: 4/9+3/7=28/63+27/63=55/63
3/4+7/24=18/24+7/24=25/24
1/3+2/9+4/27=9/27+6/27+4/27=19/27
b: 5/6-3/8=20/24-9/24=11/24
7/15-11/30=14/30-11/30=3/30=1/10
2/3+1/6-7/12
=8/12+2/12-7/12
=3/12=1/4
c: 18/25*15/6=15/25*18/6=3*3/5=9/5
30/49:6/7=30/49*7/6=210/294=5/7
1/2*3/4:6/5=3/8*5/6=15/48=5/16
d: 8*3/5:12/5=24/5*5/12=2
4:9/5:10/3=4*5/9*3/10=2/3
a) \(\dfrac{-2}{15}\times x=\dfrac{-2}{7}\) b) \(\dfrac{7}{-5}\times x=-3\) c) \(-\dfrac{4}{9}x=\dfrac{1}{2}\) d) \(\dfrac{8}{3}\div x=\dfrac{-3}{8}\)
e) \(x\div\dfrac{3}{-4}=-12\) f) \(\left(-1\right)\div x=\dfrac{-3}{7}+\dfrac{4}{5}\) g)\(\dfrac{4}{11}x-\dfrac{1}{3}=\dfrac{2}{5}\) i) \(\dfrac{-6}{7}-\dfrac{1}{5}x=-4\)
j) \(\dfrac{1}{2}+\dfrac{2}{3}\div7=\dfrac{-1}{3}\) k) \(\dfrac{-5}{2}+x\div7=\dfrac{-1}{3}\) L) \(\dfrac{-3}{2}-\dfrac{1}{4}\div x=-1\)
a: =>x*2/15=2/7
=>x=2/7:2/15=2/7*15/2=15/7
b: x=3:7/5=15/7
c: x=-1/2:4/9=-1/2*9/4=-9/8
d: x=-8/3:3/8=-64/9
g: =>4/11x=2/5+1/3=6/15+5/15=11/15
=>x=11/15:4/11=121/60
l: =>1/4:x=1-3/2=-1/2
=>x=-1/4:1/2=-1/4*2=-1/2
k: =>x:7=-1/3+5/2=-2/6+15/6=13/6
=>x=91/6
Điền dấu thích hợp (>,<,=) vào chỗ trống.
a,\(\dfrac{-3}{5}+\dfrac{-11}{5}...\dfrac{-7}{3}+\dfrac{4}{7}\)
b,\(\dfrac{-7}{11}+\dfrac{-15}{11}...\dfrac{-4}{3}+\dfrac{-7}{5}\)
Giúp mk nha :>>. Mk cảm ơn.