khác khối có làm đc ko? nếu đc thì bn đăng câu hỏi lên nhé!

ko phải lớp 4 ko trả lời được hả?

Bài 1: 

AB;AC;AD;BC;BD;CD

HK = 6+8 = 14 cm

\(y+\frac{1}{2}\cdot\frac{1}{3}=\frac{3}{4}\)

\(y+\frac{1}{6}=\frac{3}{4}\)

\(y=\frac{3}{4}-\frac{1}{6}\)

\(y=\frac{7}{12}\)

\(y\)\(+\)\(\frac{1}{2}\)X   \(\frac{1}{3}\)\(=\)\(\frac{3}{4}\)

\(y\)\(+\)\(\frac{1}{6}\)               \(=\)\(\frac{3}{4}\)

\(y\)                               \(=\)\(\frac{7}{12}\)

1. A: 8, B: 0

Câu 2

A:3

B:0

bài 2 

= \(\frac{92}{135}\)

\(\left(\frac{1}{3}+\frac{4}{2}\cdot\frac{1}{2}\right):\left(\frac{18}{9}-113\right)\)

\(=\left(\frac{1}{3}+1\right):\left(2-113\right)\)

\(=\frac{4}{3}:\left(-111\right)\)

\(=\frac{-4}{333}\)

Bài 1:

1: \(\frac{4}{15}+\frac{11}{15}=\frac{4+11}{15}=\frac{15}{15}=1\)

2: \(\frac56+\frac{14}{12}=\frac56+\frac76=\frac{5+7}{6}=\frac{12}{6}=2\)

3: \(3+\frac35=\frac{15}{5}+\frac35=\frac{15+3}{5}=\frac{18}{5}\)

4: \(\frac{15}{13}-\frac{2}{13}=\frac{15-2}{13}=\frac{13}{13}=1\)

5: \(\frac34-\frac13=\frac{9}{12}-\frac{4}{12}=\frac{9-4}{12}=\frac{5}{12}\)

6: \(\frac35-\frac{6}{15}=\frac35-\frac25=\frac{3-2}{5}=\frac15\)

7: \(\frac{18}{5}-3=\frac{18}{5}-\frac{15}{5}=\frac{18-15}{5}=\frac35\)

8: \(7-\frac57=\frac{49}{7}-\frac57=\frac{49-5}{7}=\frac{44}{7}\)

9: \(\frac67\cdot\frac{14}{36}=\frac{6}{36}\cdot\frac{14}{7}=2\cdot\frac16=\frac26=\frac13\)

10: \(3\cdot\frac79=\frac{3\cdot7}{9}=\frac{21}{9}=\frac73\)

11: \(\frac{5}{42}\cdot21=5\cdot\frac{21}{42}=5\cdot\frac12=\frac52\)

12: \(\frac59:\frac{15}{9}=\frac59\cdot\frac{9}{15}=\frac{5}{15}=\frac13\)

13: \(\frac{35}{18}:5=\frac{35}{18\cdot5}=\frac{35}{90}=\frac{7}{18}\)

14: \(14:\frac{7}{11}=14\cdot\frac{11}{7}=2\cdot11=22\)

Bài 2:

1: \(\frac17+\frac{3}{11}+\frac27+\frac{8}{11}+\frac47+2010\)

\(=\left(\frac17+\frac27+\frac47\right)+\left(\frac{3}{11}+\frac{8}{11}\right)+2010\)

=1+1+2010

=2012

2: \(\frac23-\frac34+\frac45-\frac56+\frac67-\frac78+\frac78-\frac67+\frac56-\frac43+\frac34-\frac23+\frac{1}{2012}\)

\(=\left(\frac23-\frac23\right)+\left(\frac34-\frac34\right)+\left(\frac45-\frac45\right)+\left(\frac56-\frac56\right)+\left(\frac78-\frac78\right)+\left(\frac67-\frac67\right)\) +1/2012

=1/2012

3: \(\frac{1}{20}+\frac{1}{30}+\frac{1}{42}+\cdots+\frac{1}{380}\)

\(=\frac{1}{4\cdot5}+\frac{1}{5\cdot6}+\cdots+\frac{1}{19\cdot20}\)

\(=\frac14-\frac15+\frac15-\frac16+\cdots+\frac{1}{19}-\frac{1}{20}\)

\(=\frac14-\frac{1}{20}=\frac{5}{20}-\frac{1}{20}=\frac{4}{20}=\frac15\)

4: \(182\cdot\left\lbrack\frac{1+\frac15-\frac27+\frac{5}{13}}{2+\frac25-\frac47+\frac{10}{13}}:\frac{4-\frac{4}{33}-\frac{4}{57}+\frac{4}{7000}}{1-\frac{1}{33}-\frac{1}{57}+\frac{1}{7000}}\right\rbrack:\frac{919191}{808080}\)

\(=182\cdot\left\lbrack\frac{1+\frac15-\frac27+\frac{5}{13}}{2\left(1+\frac15-\frac27+\frac{5}{13}\right)}:\frac{4\left(1-\frac{1}{33}-\frac{1}{57}+\frac{1}{7000}\right)}{1-\frac{1}{33}-\frac{1}{57}+\frac{1}{7000}}\right\rbrack:\frac{91}{80}\)

\(=182\cdot\left\lbrack\frac12:4\right\rbrack\cdot\frac{80}{91}=80\cdot2\cdot\frac18=\frac{160}{8}=20\)