a) \(\frac{11}{15}+\frac{5}{7}+\frac{2}{7}+\frac{4}{15}=\left(\frac{11}{15}+\frac{4}{15}\right)+\left(\frac{5}{7}+\frac{2}{7}\right)\)

\(=2\)

b) \(\frac{5}{9}\times\frac{1}{2}\times\frac{5}{9}\times\frac{6}{4}=\frac{25}{81}\times\frac{3}{4}=\frac{25}{108}\)

c) \(\frac{7}{8}\div\frac{1}{2}+\frac{9}{8}\div\frac{1}{2}=\left(\frac{7}{8}+\frac{9}{8}\right)\div\frac{1}{2}\)

\(=2\div\frac{1}{2}=4\)

d) \(\frac{17}{10}+\frac{1}{2}-\frac{7}{10}=\left(\frac{17}{10}-\frac{7}{10}\right)+\frac{1}{2}\)

\(=1+\frac{1}{2}=\frac{3}{2}\)

a) \(\frac{11}{15}+\frac{5}{7}+\frac{2}{7}+\frac{4}{15}\)

\(=\left(\frac{11}{15}+\frac{4}{15}\right)+\left(\frac{5}{7}+\frac{2}{7}\right)\)

\(=1+1\)

\(=2\)

b) \(\frac{5}{9}.\frac{1}{2}.\frac{5}{9}.\frac{6}{4}\)

\(=\left(\frac{5}{9}\right)^2\left(\frac{1}{2}.\frac{6}{4}\right)\)

\(=\frac{25}{81}.\frac{3}{4}\)

\(=\frac{25}{108}\)

c) \(\frac{7}{8}:\frac{1}{2}+\frac{9}{8}:\frac{1}{2}\)

\(=\frac{7}{8}.2+\frac{9}{8}.2\)

\(=2\left(\frac{7}{8}+\frac{9}{8}\right)\)

\(=2.\frac{16}{8}\)

\(=2.2\)

\(=4\)

d) \(\frac{17}{10}+\frac{1}{2}-\frac{7}{10}\)

\(=\left(\frac{17}{10}-\frac{7}{10}\right)+\frac{1}{2}\)

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

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

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

a,(11/15+4/15)+(5/7+2/7)

=1+1

=2

b,5/9x(1/2+6/4)

=5/9x2

=10/9

c,1/2:(7/8+9/8)

=1/2:2

=1

d,(17/10-7/10)+1/2

=1+1/2

=3/2

1 nha

chúc bạn học tốt

click cho mình xin 1 điểm hỏi đáp

ok

\(\frac{1}{2}\)x \(\frac{9}{10}\)+ \(\frac{8}{10}\)+ \(\frac{2}{4}\)+ \(\frac{3}{10}\)x \(0,5\)

= \(0,5\)x \(0,9\)+ \(0,8\)+ \(0,5\)x \(0,5\)

\(=0,45\)x \(1,3\)x \(0,5\)

\(=0,45\)x \(0,65=0,2925\)

a ) (11/15+4/15 ) + ( 5/7 +2 /7 )

=1+1

= 2

b)5/9 x ( 1/ 2 + 6/ 4 )

= 5/9 x 2

=10/9 

c) 17/10-5/10-7/10

=(17-5-7) / 10

= 5/10

câu 5: tận cùng bằng 9

câu 13: đáp án A

k nha

7×6×3=42×3=126(cây)

9×8×3=72×3=216(cây)

10×5×4=50×4=200(cây)

7×5×3=35×3=105(cây)

9×10×3=90×3=270(cây)

11×10×3=110×3=330(cây)

10×10×3=100×3=300(cây)

Nhớ

a,

b,

c,

đây là e

c,

d,

f,

g,

\(a,3\frac{3}{10}+x=5\frac{3}{10}\)

\(\frac{33}{10}+x=\frac{53}{10}\)

\(x=\frac{53}{10}-\frac{33}{10}\)

\(x=2\)

\(b,4\frac{2}{9}-x=\frac{2}{9}\)

\(x=4\frac{2}{9}-\frac{2}{9}\)

\(x=4\)

kí hiệu U trong tập hợp có tác dụng gì ??????????????

hãy ví dụ một phép tính xem

giúp mình nhé mình đang cần gấp

1) \(4\frac{3}{10}=\frac{43}{10};21\frac{7}{100}=\frac{2107}{100};7\frac{39}{100}=\frac{739}{100};6\frac{123}{1000}=\frac{6123}{1000}\)

2)\(a,5\frac{2}{10}+7\frac{1}{10}=\frac{52}{10}+\frac{71}{10}=\frac{123}{10}\)

\(b,5\frac{6}{7}-3\frac{5}{7}=\frac{41}{7}-\frac{26}{7}=\frac{15}{7}\)

\(c,8\frac{3}{5}x2\frac{6}{7}=\frac{43}{5}x\frac{20}{7}=\frac{172}{7}\)

\(d,1\frac{3}{10}:5\frac{7}{8}=\frac{13}{10}:\frac{47}{8}=\frac{13}{10}x\frac{47}{8}=\frac{611}{80}\)

3) \(7\frac{9}{10}và4\frac{9}{10}\)

Ta có: \(7\frac{9}{10}=\frac{79}{10};4\frac{9}{10}=\frac{49}{10}\)

Suy ra: \(\frac{79}{10}>\frac{49}{10}hay7\frac{9}{10}>4\frac{9}{10}\)

 \(6\frac{3}{10}và6\frac{5}{9}\)

Ta có: \(6\frac{3}{10}=\frac{63}{10};6\frac{5}{9}=\frac{59}{9}\)

Suy ra: \(\frac{63}{10}>\frac{59}{9}hay6\frac{3}{10}>6\frac{5}{9}\)

óc chó mới đi hỏi câu này.Đúng là óc chó thật

\(\left(x+\frac{3}{4}\right)\times\frac{5}{7}=\frac{10}{9}\)

\(\Rightarrow x+\frac{3}{4}=\frac{10}{9}:\frac{5}{7}=\frac{10}{9}\times\frac{7}{5}=\frac{14}{9}\)

\(\Rightarrow x=\frac{14}{9}-\frac{3}{4}=\frac{56-27}{36}=\frac{29}{36}\)

\(\left(x+\frac{3}{4}\right)\times\frac{5}{7}=\frac{10}{9}\)

\(\Leftrightarrow x+\frac{3}{4}=\frac{14}{9}\)

\(\Rightarrow x=\frac{29}{36}\)

P/s tham khảo nha