Giúp 

a) \(\dfrac{2}{9}+\dfrac{3}{5}-\dfrac{1}{15}=\dfrac{37}{45}-\dfrac{1}{15}=\dfrac{37}{45}-\dfrac{3}{45}=\dfrac{34}{45}\)

b) \(\dfrac{5}{12}\times\dfrac{4}{5}\div4=\dfrac{1}{3}\div4=\dfrac{1}{12}\)

c) \(\dfrac{8}{9}-\dfrac{4}{15}\div\dfrac{2}{5}=\dfrac{8}{9}-\dfrac{2}{3}=\dfrac{8}{9}-\dfrac{6}{9}=\dfrac{2}{9}\)

a ) \(\dfrac{2}{9}+\dfrac{3}{5}-\dfrac{1}{15}=\dfrac{37}{45}-\dfrac{1}{15}=\dfrac{37}{45}-\dfrac{3}{45}=\dfrac{34}{45}\)

b)\(\dfrac{5}{12}x\dfrac{4}{5}:4=\dfrac{1}{3}:4=\dfrac{1}{12}\)

c) \(\dfrac{8}{9}-\dfrac{4}{15}:\dfrac{2}{5}=\dfrac{8}{9}-\dfrac{2}{3}=\dfrac{8}{9}-\dfrac{6}{9}=\dfrac{2}{9}\)

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: \(\dfrac{17}{-26}\cdot\left(\dfrac{1}{6}-\dfrac{5}{3}\right):\dfrac{17}{13}-\dfrac{20}{3}\left(\dfrac{2}{5}-\dfrac{1}{4}\right)+\dfrac{2}{3}\left(\dfrac{6}{5}-\dfrac{9}{2}\right)\)

\(=\dfrac{-17}{26}\cdot\dfrac{13}{17}\cdot\dfrac{-3}{2}-\dfrac{20}{3}\cdot\dfrac{3}{20}+\dfrac{2}{3}\cdot\dfrac{-33}{10}\)

\(=\dfrac{3}{4}-1-\dfrac{11}{5}\)

\(=-\dfrac{49}{20}\)

2006 x [43 x 10 - 2 x 43 x 5] +100

=2006x0+100

=0+100

=100

64x4+18x4+9x8

=256+72+72

=400

44x5+18x10+20x5

=220+180+100

=500

3x4+4x6+9x2+18

=12+24+18+18

=72

2x5+5x7+9x3

=10+35+27

=72

15:5+27:5+8:5

=[15+27+8]:5

=10

99:5-26:5-14:5

=[99-26-14]:5

=11.8

Câu cuối sai đề nha mà nếu đề như vậy thì đó là toán lớp 6

Cảm ơn bạn I LOVE YOU rất nhiều mình đang vội ,cảm ơn bạn nhé!!!

Trả lời:

\(2006\times\left(43\times10-2\times43\times5\right)+100\)

\(=2006\times\left(43\times10-43\times10\right)+100\)

\(=2006\times0+100\)

\(=0+100\)

\(=100\)

\(44\times5+18\times10+20\times5\)

\(=44\times5+18\times2\times5+20\times5\)

\(=44\times5+36\times5+20\times5\)

\(=5\times\left(44+36+20\right)\)

\(=5\times100\)

\(=500\)

\(3\times4+4\times6+9\times2+18\)

\(=12+24+18+18\)

\(=12+24+36\)

\(=72\)

\(2\times5+5\times7+9\times3\)

\(=5\times\left(2+7\right)+9\times3\)

\(=5\times9+9\times3\)

\(=9\times\left(5+3\right)\)

\(=9\times8\)

\(=72\)

\(15\div5+27\div5+8\div5\)

\(=\left(15+27+8\right)\div5\)

\(=50\div5\)

\(=10\)

\(99\div5-26\div5-14\div5\)

\(=\left(99-26-14\right)\div5\)

\(=59\div5\)

\(=\frac{59}{5}\)

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17+18 = 171 nhé

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17+18.  = 171

a) \(\dfrac{2}{5}-\dfrac{3}{15}\)

\(=\dfrac{2}{5}-\dfrac{3:3}{15:3}\)

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

\(=\dfrac{1}{5}\)

b) \(\dfrac{9}{27}-\dfrac{2}{9}\)

\(=\dfrac{9:3}{27:3}-\dfrac{2}{9}\)

\(=\dfrac{3}{9}-\dfrac{2}{9}\)

\(=\dfrac{1}{9}\)

c) \(\dfrac{18}{24}-\dfrac{4}{8}\)

\(=\dfrac{18:6}{24:6}-\dfrac{4:2}{8:2}\)

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

\(=\dfrac{1}{4}\)

d) \(\dfrac{6}{16}-\dfrac{10}{64}\)

\(=\dfrac{6\times2}{16\times2}-\dfrac{10:2}{64:2}\)

\(=\dfrac{12}{32}-\dfrac{5}{32}\)

\(=\dfrac{7}{32}\)

a: \(=\dfrac{6}{7}\cdot\dfrac{-3}{5}=\dfrac{-18}{35}\)

b: \(=\dfrac{2}{5}\cdot\dfrac{-15}{8}=\dfrac{-30}{40}=-\dfrac{3}{4}\)

c: \(=\dfrac{2}{4}\cdot\dfrac{7}{3}=\dfrac{1}{2}\cdot\dfrac{7}{3}=\dfrac{7}{6}\)

d: \(=\dfrac{8}{3}\cdot\dfrac{16}{4}=\dfrac{128}{12}=\dfrac{32}{3}\)

a)-18/35

b)-3/4

c)7/6

d)32/3

e)5/21

sai thì xin lỗi nhé bn