^{A=7 mu 2020 mu 2019-3 mu 2016 mu 2015 :5 chung to A la so chan}

a) 2345-1000:[19-2(21-18)mu 2]

b)107-{38+[7.3 mu 2-24:6+(9-7) mu 3]} :15

c) 10- [(2 mu 2-48).5+(2 mu 3 .10+8)]:28

2) tim so tu nhien a,biet rang a gan den 1000,a:12,a:21 deu co du la 5

3) tim boi chung lon hon 5000 be hon 10000 cua cac so 126;140;180.

chung minh rang 

5 mu 15 .5 mu 14+5mu 13 : cho 21

 10 mu 8+ 10 muu 7 +10 mu 6 :55

[n +3] . [n+24] :2 

so sánh 2 hiệu

2018 mu 2019- 2018 mu 2018 va  2018 mu 2017- 2018 mu 2017

Tìm X biết :

x - 5 = 7 mu 10 :7 mu 8 + 2 mu 2018  nhan ( 2 mu 4 - 4 mu 2)

tim so nguyen to p sao cho p mu 2 cộng p mu 4 cộng 1 cung la so nguyen to

Tim x,y la so nguyen 

a) 2x-3y+5= xy

b) x mu 2 +2xy+2x+4y

B2 Tim x,y la so nguyen to

x mu 2 -2y mu 2 =1 

B3 Tim so tu nhienx,y 

7 .(x-2004) mu 2 = 23- y mu 2

cac ban oi giai gium minh bai nay nhe neu ai giai duoc minh cho 1 like luon ok

chung minh rang :

10 mu n cong voi 5 mu 3 chia het cho 9

43 mu 43 tru cho 17 mu 17 chia het cho 10

nhanh nhe minh muon chu nhat la co cau tra loi cang som cang tot nhe

so du khi chia 5 mu 13+5 mu 11- 5 mu 10- 38 khi chia cho 43 la