\(\frac{15}{3}-\frac{17}{4}+\frac{2}{8}+\frac{3}{5}-\frac{7}{10}\)

\(\Leftrightarrow\frac{600}{120}-\frac{510}{120}+\frac{30}{120}+\frac{72}{120}-\frac{84}{120}\)

\(\Leftrightarrow\frac{600-510+30+72-84}{120}\)

\(\Leftrightarrow\frac{108}{120}\)

\(\Leftrightarrow\frac{108:12}{120:12}=\frac{9}{10}\)

Xin lỗi nhé

Em mới học lớp 5 nên không biết đâu

Đáp án:
1)12.

2)39.

3)68.

Giải thích các bước giải:
12÷9=1dư3.

39÷27=1 dư 12.

68÷41=1 dư 27
Sai thì mong bạn thông cảm 

-> a : 9 = 3 

             = 3 × 9

             = 27

-> a : 27 = 12

                = 12 × 27

                = 324

-> a : 41 = 27

                = 27 × 41

                = 1107

M = [1;2;3;4;]

M = { 0; 5 }

là số 26 nha 

# học tốt

là 26

HT

(mik bôi đen nhé)

a) Tony play shouldn’t with matches.           => plays 

b) What do Peter do in his free time ?          => does    

c) How many do you go to the English club ?  => (Câu này thì ko chắc lắm)

d) Tom often do karate in his free time .         => does

c) Linda often surf the Internet in his free time.     => sufts

d) Anna and Rose goes skating in their free time.    => go

e) His mother go shopping at weekends.       => goes  

g) We sometimes goes fishing in the river.   => go 

h) Look ! Jim is ride his bike too fast.      => riding     

i) I often go hiking on the forest.   => hike

a) Tony plays shouldn’t with matches.            

b) What does Peter do in his free time ?              

c) How often do you go to the English club ?  

d) Tom often does karate in his free time .         

c) Linda often sufts the Internet in his free time. 

d) Anna and Rose go skating in their free time. 

e) His mother goes shopping at weekends.          

g) We sometimes go fishing in the river.    

h) Look ! Jim is riding his bike too fast.           

i) I often go hike on the forest.   

chỗ bôi đen là mik sửa nhé

/HT\

\(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+....+\frac{2}{99.101}\)

\(=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+...+\frac{1}{99}-\frac{1}{101}\)

\(=1-\frac{1}{101}=\frac{101-1}{101}=\frac{100}{101}\)

thank

= 100/101 nha
 

Tí nữa có đpá án

Ta có: abc = 100 . a + 10 . b + c = n^2 - 1 (1)
cba = 100 . c + 10 . b + a = (n - 2)^2 = n^2 - 4n + 4 (2)
Lấy (1) trừ (2) ta được:
99 . (a - c) = 4n - 5
=> 4n - 5 chia hết cho 99
Vì 100 ≤ abc ≤ 999 nên:
100 ≤ n^2 - 1 ≤ 999 => 101 ≤ n^2 ≤ 1000 => 11 ≤ 31 => 39 ≤ 4n - 5 ≤ 119
Vì 4n - 5 chia hết cho 99 nên 4n - 5 = 99 => n = 26 => abc = 675