5+18-7 = 16

3/8+1/2-5/24=9/24 +12/24-5/24=16/24=2/3

(16+2/3):(16+2/3)=1

(120/24+9/24+432/24+12/24-168/24-5/24):(48/3+2/3)=-32/24:50/3=-4/3.3/50=-4/50=-2/25

k cho mik nha

\(a)\frac{2}{3}+\frac{7}{12}=\frac{8+7}{12}=\frac{15}{12}\)

\(\frac{25}{48}+\frac{11}{24}=\frac{25+22}{48}=\frac{47}{48}\)

P/S : Giải từng bài 

\(b)\frac{5}{7}+\frac{3}{18}=\frac{5}{7}+\frac{1}{6}=\frac{30+7}{42}=\frac{37}{42}\)

\(\frac{15}{24}+\frac{12}{16}=\frac{5}{8}+\frac{3}{4}=\frac{5+6}{8}=\frac{11}{8}\)

a) 2/5 ; 7/12 ; 49/50

b) 6/8 ; 12/16

27*26/2=351

k cho mình nha

a/ đúng

b/ sai

c/sai

d/ đúng

Đ

S

S

Đ

a Đ

b S

c S

d Đ

a ) S 

b ) Đ

c ) S

d ) Đ

k cho mk nhé 

Bài 1:

a: \(\frac{5\times7}{15}=\frac{35}{15}=\frac73\)

b: \(8:\frac{16}{23}=8\times\frac{23}{16}=\frac{8}{16}\times23=23\times\frac12=\frac{23}{2}\)

c: \(\frac{8}{15}:5=\frac{8}{15\times5}=\frac{8}{75}\)

d: \(\frac{15}{19}\times3=\frac{15\times3}{19}=\frac{45}{19}\)

Bài 2:

a: \(3\times\frac49+\frac23-\frac{7}{18}\)

\(=\frac43+\frac23-\frac{7}{18}\)

\(=\frac63-\frac{7}{18}=2-\frac{7}{18}=\frac{36}{18}-\frac{7}{18}=\frac{29}{18}\)

b: \(\frac{7}{10}\times\frac23-\frac14=\frac{14}{30}-\frac14=\frac{28}{60}-\frac{15}{60}=\frac{28-15}{60}=\frac{13}{60}\)

c: \(\frac98-\frac78:\frac56=\frac98-\frac78\times\frac65\)

\(=\frac98-\frac{42}{40}=\frac{45}{40}-\frac{42}{40}=\frac{3}{40}\)

d: \(\frac23+\frac12:\frac32-\frac{11}{24}\)

\(=\frac23+\frac12\times\frac23-\frac{11}{24}\)

\(=\frac23+\frac13-\frac{11}{24}=1-\frac{11}{24}=\frac{13}{24}\)

Bài 3:

Độ dài đáy tương ứng với chiều cao là: \(\frac35\times2=\frac65\left(m\right)\)

Chu vi hình bình hành là:

\(\left(\frac65+\frac45\right)\times2=\frac{10}{5}\times2=2\times2=4\left(m\right)\)

Diện tích bình hành là;

\(\frac65\times\frac35=\frac{18}{25}\left(m^2\right)\)

a)\(\dfrac{5}{7}+\dfrac{4}{9}=\dfrac{45}{63}+\dfrac{28}{63}=\dfrac{73}{63}\) ; \(\dfrac{9}{11}+\dfrac{3}{8}=\dfrac{72}{88}+\dfrac{33}{88}=\dfrac{105}{88}\)

\(\dfrac{4}{5}-\dfrac{2}{3}=\dfrac{12}{15}-\dfrac{10}{15}=\dfrac{2}{15}\); \(\dfrac{16}{25}-\dfrac{2}{5}=\dfrac{16}{25}-\dfrac{10}{25}=\dfrac{6}{25}\)

b)\(5+\dfrac{3}{5}=\dfrac{25}{5}+\dfrac{3}{5}=\dfrac{28}{5};10-\dfrac{9}{16}=\dfrac{160}{16}-\dfrac{9}{16}=\dfrac{151}{16}\)

\(\dfrac{2}{3}-\left(\dfrac{1}{6}+\dfrac{1}{8}\right)=\dfrac{2}{3}-\left(\dfrac{8}{48}+\dfrac{6}{48}\right)=\dfrac{2}{3}-\dfrac{14}{48}=\dfrac{32}{48}-\dfrac{14}{48}=\dfrac{3}{8}\)

Nay rảnh lại qua làm mấy bài lớp 4 ^^

Tui làm luôn kh ghi đề nhá

1, 

\(\frac{2}{3}+\frac{8}{15}=\frac{6}{5}\)

\(\frac{2}{5}+\frac{2}{3}=\frac{16}{15}\)

\(\frac{2}{3}+\frac{5}{6}=\frac{3}{2}\)

2, 

\(\cdot\frac{3}{7}+\frac{6}{5}+\frac{4}{7}\)

\(=\frac{3}{7}+\frac{4}{7}+\frac{6}{5}\)

\(=1+\frac{6}{5}\)

\(=\frac{11}{5}\)

\(\cdot\frac{6}{4}+\frac{7}{3}+\frac{4}{4}+\frac{3}{3}\)

\(=\frac{6}{4}+\frac{4}{4}+\frac{7}{3}+\frac{3}{3}\)

\(=\frac{10}{4}+\frac{10}{3}\)

\(=\frac{35}{6}\)

2,