Ta có : \(\frac{\left(\frac{2}{5}\right)^9.10^9-\left(\frac{-9}{4}\right)^5:\left(\frac{-3}{16}\right)^{10}}{4^{12}+16^9}\)

=\(\frac{\left(\frac{2}{5}.10\right)^9-\left[\left(\frac{-3}{2}\right)^2\right]^5:\left(\frac{-3}{16}\right)^{10}}{\left(2^2\right)^{12}+\left(2^4\right)^9}\)=\(\frac{4^9-\left(\frac{-3}{2}\right)^{10}:\left(\frac{-3}{16}\right)^{10}}{2^{24}+2^{36}}\)=\(\frac{4^9-\left[\left(\frac{-3}{2}\right):\left(\frac{-3}{16}\right)\right]^{10}}{2^{24}\left(1+2^{12}\right)}\)

=\(\frac{\left(2^2\right)^9-8^{10}}{2^{24}\left(1+2^{12}\right)}\)=\(\frac{\left(2^2\right)^9-\left(2^3\right)^{10}}{2^{24}\left(1+2^{12}\right)}\)=\(\frac{2^{18}-2^{30}}{2^{24}\left(1+2^{12}\right)}\)=\(\frac{2^{18}\left(1-2^{12}\right)}{2^{24}\left(1+2^{12}\right)}\)=\(\frac{1-2^{12}}{2^6\left(1+2^{12}\right)}\)

Không biết đúng hong nha!

cách giải bài này như nào: 5/20+1/4+6/24+8/32=bao nhiêu

    \(\dfrac{4}{5}\) : (\(\dfrac{4}{5}\) .- \(\dfrac{5}{4}\)) : (\(\dfrac{16}{25}\) - \(\dfrac{1}{5}\))

=  \(\dfrac{4}{5}\) : (-1) : (\(\dfrac{16}{25}\) - \(\dfrac{5}{25}\))

= -\(\dfrac{4}{5}\)  : \(\dfrac{11}{25}\)

= - \(\dfrac{4}{5}\) x \(\dfrac{25}{11}\)

=  - \(\dfrac{20}{11}\)

    \(\dfrac{11}{12}\) : (\(\dfrac{7}{9}\) + \(\dfrac{-1}{3}\)) - (\(\dfrac{2}{3}\) - \(\dfrac{5}{15}\))

= \(\dfrac{11}{12}\) : (\(\dfrac{7}{9}\) - \(\dfrac{3}{9}\)) - (\(\dfrac{2}{3}\) - \(\dfrac{1}{3}\))

= \(\dfrac{11}{12}\) : \(\dfrac{4}{9}\) - \(\dfrac{1}{3}\)

= \(\dfrac{11}{12}\) x \(\dfrac{9}{4}\) - \(\dfrac{1}{3}\)

= \(\dfrac{99}{48}\) - \(\dfrac{1}{3}\)

= \(\dfrac{99}{48}\) - \(\dfrac{16}{48}\)

= \(\dfrac{83}{48}\)  

\(\dfrac{4}{5}\): (\(\dfrac{4}{5}\).-\(\dfrac{5}{4}\)) : (\(\dfrac{16}{25}\) - \(\dfrac{1}{5}\))

=\(\dfrac{4}{5}\) x - 1: (\(\dfrac{16}{25}\) - \(\dfrac{5}{25}\))

= - \(\dfrac{4}{5}\) : \(\dfrac{11}{25}\)

= - \(\dfrac{4}{5}\) x \(\dfrac{25}{11}\)

= - \(\dfrac{20}{11}\) 

\(\dfrac{11}{12}\): (\(\dfrac{7}{9}\) + - \(\dfrac{1}{3}\)) - (\(\dfrac{2}{3}\) - \(\dfrac{5}{15}\))

= \(\dfrac{11}{12}\) : (\(\dfrac{7}{9}\) - \(\dfrac{3}{9}\)) - (\(\dfrac{2}{3}\) - \(\dfrac{1}{3}\))

= \(\dfrac{11}{12}\) : \(\dfrac{4}{9}\) - \(\dfrac{1}{3}\)

= \(\dfrac{11}{12}\) x \(\dfrac{9}{4}\) - \(\dfrac{1}{3}\)

= \(\dfrac{99}{48}\) - \(\dfrac{16}{48}\)

= \(\dfrac{83}{48}\) 

- \(\dfrac{2}{5}\).(\(\dfrac{9}{8}\) + \(\dfrac{16}{32}\) - \(\dfrac{3}{4}\)) - \(\dfrac{9}{10}\)

= - \(\dfrac{2}{5}\).(\(\dfrac{9}{8}\) + \(\dfrac{4}{8}\) - \(\dfrac{6}{8}\)) - \(\dfrac{9}{10}\)

= - \(\dfrac{2}{5}\).(\(\dfrac{13}{8}\) - \(\dfrac{6}{8}\)) - \(\dfrac{9}{10}\)

= - \(\dfrac{2}{5}\).\(\dfrac{7}{8}\) - \(\dfrac{9}{10}\)

= - \(\dfrac{7}{20}\) - \(\dfrac{18}{20}\)

= - \(\dfrac{5}{4}\)

1)` 2/9 + -3/4 + 5/30= (40+(-135) + 30 )/180 = -65/180 = -13/36`

2) `-7/12 - 11/18=(-21)/36 - 22/36 = -43/36 `

3) `7/8 - (-5)/16=14/16- (-5)/16 = 19/16 `

4) `3/8 - (-9)/10 - 5/16= (30- (-72) -25)/80=77/80`

1)\(\dfrac{2}{9}+\dfrac{-3}{4}+\dfrac{5}{30}\)

\(=\dfrac{2.20}{9.20}+\dfrac{-3.45}{4.45}+\dfrac{5.6}{30.6}\)

\(=\dfrac{40}{180}+\dfrac{-135}{180}+\dfrac{30}{180}\)

\(=\dfrac{40+\left(-135\right)+30}{180}\)

\(=\dfrac{-65}{180}\)

\(=\dfrac{-13}{36}\)

2)\(\dfrac{-7}{12}-\dfrac{11}{18}\)

\(=\dfrac{-7.3}{12.3}-\dfrac{11.2}{18.2}\)

\(=\dfrac{-21}{36}-\dfrac{22}{36}\)

\(=\dfrac{-21-22}{36}\)

\(=\dfrac{-43}{36}\)

3)\(\dfrac{7}{8}-\dfrac{-5}{16}\)

\(=\dfrac{7.2}{8.2}-\dfrac{-5}{16}\)

\(=\dfrac{14}{16}-\dfrac{-5}{16}\)

\(=\dfrac{14-\left(-5\right)}{16}\)

\(=\dfrac{19}{16}\)

4)\(\dfrac{3}{8}-\dfrac{-9}{10}-\dfrac{5}{16}\)

\(=\dfrac{3.10}{8.10}-\dfrac{-9.8}{10.8}-\dfrac{5.5}{16.5}\)

\(=\dfrac{30}{80}-\dfrac{-72}{80}-\dfrac{25}{80}\)

\(=\dfrac{30-\left(-72\right)-25}{80}\)

\(=\dfrac{77}{80}\)

Phương pháp giải:

Tính nhẩm rồi điền kết quả vào chỗ trống.

Lời giải chi tiết:

a)

7 + 5 = 12        5 + 7 = 12

4 + 9 = 13        9 + 4 = 13

8 + 7 = 15        7 + 8 = 15

2 + 9 = 11        9 + 2 = 11

b)

16 − 8 = 8        14 − 7 = 7

11 − 9 = 2        17 − 9 = 8

12 − 5 = 7        16 − 9 = 7

13 − 6 = 7        15 − 8 = 7

7+5=17        5+7=17

4+9=13       9+4=13

Phương pháp giải:

Tính nhẩm các số rồi điền kết quả vào chỗ trống.

Lời giải chi tiết:

Tính nhẩm: