45 x 77 + 9 x 22 x 5 + 45

= 45 x 77 + 45 x 22 + 45

= 45 x (77 + 22 + 1)

= 45 x 100

= 4500

k mik nhé

45x22+9x22x5+45=3465+990+45

=4500

\(45x77+9x22x5+45\)

\(=45x77+45x22+45\)

\(=45x\left(77+22+1\right)\)

\(=45x100\)

\(=4500\)

2 - 5/7 + 9/21 = 12/7

5/8 : 3 x 24/25 = 1/5

k minh di

2 - \(\frac{5}{7}\)+\(\frac{9}{21}\)= \(\frac{9}{7}\)+\(\frac{9}{21}\)= \(\frac{12}{7}\)

\(\frac{5}{8}\): 3 x\(\frac{24}{25}\)= \(\frac{5}{24}\)x \(\frac{24}{25}\)= \(\frac{1}{5}\)

mk nhanh nhất tk mk nha

\(\frac{2}{3}\times\frac{1}{5}+\frac{3}{10}\times\frac{2}{3}+\frac{4}{6}\times\frac{1}{2}\)

\(=\frac{2}{3}\times\frac{1}{5}+\frac{3}{10}\times\frac{2}{3}+\frac{2}{3}\times\frac{1}{2}\)

\(=\frac{2}{3}\times\left(\frac{1}{5}+\frac{3}{10}+\frac{1}{2}\right)\)

\(=\frac{2}{3}\times\frac{10}{10}\)

\(=\frac{2}{3}\)

2/3 x 1/6 x 9/11 

= 1/9 x 9/11

= 1/11

1/11 nhé bn tk mk nhé mk sẽ kb

(2/3x1/6)x9/11

= 1/9x9/11

=1/11

\(x+\frac{5}{13}+\frac{10}{26}+\frac{15}{39}+\frac{20}{52}+\frac{401}{104}=\frac{25}{13}.\)

\(\Rightarrow x+\left(\frac{5}{13}+\frac{10}{26}+\frac{15}{39}+\frac{20}{52}+\frac{40}{104}\right)=\frac{25}{13}\)

\(\Rightarrow x+\frac{25}{13}=\frac{25}{13}\)

\(\Rightarrow x=\frac{25}{13}-\frac{25}{13}\)

\(\Rightarrow x=0\)

\(\leftrightarrow k-nha!!!!\)

\(x+\frac{5}{13}+\frac{10}{26}+\frac{15}{39}+\frac{20}{52}+\frac{40}{104}=\frac{25}{13}\)                                                                                                                   \(x+\left(\frac{5}{13}+\frac{10}{26}+\frac{15}{39}+\frac{20}{52}+\frac{40}{104}\right)=\frac{25}{13}\)                                                                                                            \(x+\frac{25}{13}\)                                                     \(=\frac{25}{13}\)                                                                                                           \(x\)                                                                   \(=\frac{25}{13}-\frac{25}{13}\)                                                                                             \(x=0\)

2820 +2820+2820+2820-2820x3=2820x1+2820x1+2820x1+2820x1-2820x3=2820x(1+1+1+1-3)=2820x1=2820

25380

2820×4-2820×3

2820×(4-3)

2820×1

2820

2/3×3/4×4/5÷1/5=2

2/5×3/4×5/6÷3/4=0.33333333333......

2/3 x 3/4 x 4/5 : 1/5 = 6/12 x 4/5 :1/5 = 24/60 :1/5 = 4/10 : 1/5 = 4/10 x 5/1 = 20/10 = 2

2/5 x 3/4 x 5/6 : 3/4 = 6/20 x 5/6 : 3/4 = 3/10 x 5/6  : 3/4 = 15/60 : 3/4 = 1/4 : 3/4 = 1/4 x 4/3 = 4/12 = 1/3

k cho mk nha!

\(\frac{2}{3}\times\frac{3}{4}\times\frac{4}{5}\div\frac{1}{5}\)

\(=\frac{2}{3}\times\frac{3}{4}\times\frac{4}{5}\times\frac{5}{1}\)

\(=\frac{2\times3\times4\times5}{3\times4\times5\times1}\)

\(=\frac{2}{1}\)

\(=2\)

\(\frac{321x322x323x324}{322x323x324x321}\)=\(1\)

\(\frac{321}{322}.\frac{322}{323}.\frac{323}{324}.\frac{324}{321}\)

Rút gọn số 322 với 322 rồi các số kia nữa thì dc

\(\frac{321}{321}=1\)

ta thấy các tử số và mẫu số giống nhau nên ta gạch chéo những cặp giống nhau và ta được kết quả là 1

12/13 + 2/7 + 8/13 + 6/13 + 5/7

= ( 2/7 + 5/7 ) + ( 12/13 + 8/13 + 6/13 )

= 1 + 2

= 3

=(12/13+8/13+6/13)+(2/7+5/7)=2+1=3

12/13+2/7+8/13+6/13+5/7

   =(12/13+8/13+6/13)+(2/7+5/7)

   =2+1

   =3