a, Sai

b, Đúng

c, đúng 

d, Sai

a,\(2\frac{2}{5}+1\frac{2}{5}=3\frac{2}{5}\left(S\right)\)

b,\(6\frac{3}{4}-1\frac{1}{4}=5\frac{2}{4}\left(\text{Đ}\right)\)

c,\(3\frac{1}{2}\times2\frac{2}{3}=9\frac{1}{3}\left(\text{Đ}\right)\)

d,\(4\frac{1}{6}\div2\frac{1}{5}=2\frac{5}{6}\left(S\right)\)

a, 6/9+5/7+1/3=2/3+5/7+1/3=5/7+1=12/7

b, 17/7+6/5-20/14=17/7+6/5-10/7=6/5+1=11/5

c,2/5x1/4+3/4x2/5=2/5x(1/4+3/4)=2/5x1=2/5

d, 6/11:4/6+5/11:2/3=6/11:2/3+5/11:2/3=(6/11+5/11):2/3=3/2

nha

đưa hết hỗn số về dạng phân số rồi quy đồng bình thường ạ !

Hoàng_Linh_Nga làm đc thì làm nhé.

Giải:

\(2\frac{1}{6}+3\frac{2}{3}\)

\(=\frac{13}{12}+\frac{11}{9}\)

\(=\frac{249}{108}\)

\(4\frac{3}{4}-3\frac{5}{6}\)

\(=\frac{19}{16}-\frac{23}{18}\)

\(=\frac{342}{288}-\frac{368}{288}\)

\(=\frac{-26}{288}\)xem lại đề đi nhé

\(9\frac{1}{6}\times4\frac{2}{3}\)

\(=\frac{55}{18}\times\frac{15}{12}\)

\(=\frac{825}{216}\)

\(2\frac{5}{7}:\frac{14}{5}\)

\(=\frac{19}{7}:\frac{14}{5}\)

\(=\frac{95}{98}\)

\(\frac{23}{12}\)

\(\frac{314}{105}\)

\(\frac{59}{60}\)

\(\frac{199}{90}\)

\(\frac{1}{18}\)

\(\frac{13}{36}\)

\(\frac{4}{221}\)

\(\frac{4}{85}\)

phải giải thích đày đủ

\(\frac{5}{6}\)x\(\frac{3}{3}\)+\(\frac{2}{6}\)- 5\(\frac{2}{4}\)

=\(\frac{5}{6}\)+\(\frac{2}{6}\)-\(\frac{1}{10}\)

=\(\frac{7}{6}\)-\(\frac{1}{10}\)

=\(\frac{64}{60}\)=\(\frac{16}{15}\)

CHÚC BẠN HỌC TỐT

bn tự ra câu hỏi tự trả lời luôn à!

\(3+\frac{2}{5}-\frac{3}{4}\times\frac{4}{5}\)

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

\(=3+1\)

\(=4\)

\(\frac{9}{5}\div\frac{7}{6}+\frac{3}{2}\div\frac{7}{6}-\frac{8}{5}\times\frac{6}{7}\)

\(=\frac{9}{5}\times\frac{6}{7}+\frac{3}{2}\times\frac{6}{7}-\frac{8}{5}\times\frac{6}{7}\)

\(=\frac{6}{7}\times\left(\frac{9}{5}+\frac{3}{2}-\frac{8}{5}\right)\)

\(=\frac{6}{7}\times\frac{17}{10}\)

\(=\frac{102}{70}\)

\(=\frac{51}{35}\)

\(\frac{9}{5}:\frac{7}{6}+\frac{3}{2}:\frac{7}{6}-\frac{8}{5}x\frac{6}{7}\)

\(=\frac{9}{5}x\frac{6}{7}+\frac{3}{2}x\frac{6}{7}-\frac{8}{5}x\frac{6}{7}\)

\(=\frac{7}{6}x\left(\frac{9}{5}+\frac{3}{2}-\frac{8}{5}\right)\)

\(=\frac{7}{6}x\frac{17}{10}\)

\(=\frac{119}{60}\)

\(x\)là dấu nhân

b

Q=\(\frac{2}{6}+\frac{2}{12}+\frac{2}{20}+...+\frac{2}{9900}\)

Rồi giải tương tự như câu a là được

M=\(5\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\right)=5\left(1-\frac{1}{100}\right)=5.\frac{99}{100}=\frac{99}{20}\)