Bài 3:a)A=108/119.107/211+108/119.104/211
=108/119.(107/211+104/211)
=108/119.211/211
=108/119.1
=108/119
b)15/19.27/33+15/19.19/33-15/19.13/33
=15/19.(27/33+19/33-13/33)
=15/19.(46/33-13/33)
=15/19.33/33
=15/19.1
=15/19
c)4/20+16/42+6/15+(-3/5)+2/21+(-10/21)+3/20
=(4/20+3/20)+(6/15-9/15)+(16/42+4/42-20/42)
=7/20+(-3/15)+0/42
=7/20-1/5
=7/20-4/20
=3/20
d)-3/4.2/11+(-3/4).9/11+2và3/4
=(-3/4).(2/11+9/11)+2và3/4
=-3/4.11/11+2và3/4
=-3/4.1+2+3/4
=(3/4-3/4)+2
=2
e)125%.(-1/2)^2÷(1và5/16-1,5)+2008^0
=5/4.1/4÷(21/16-3/2)+1
=5/16÷(21/16-24/16)+1
=5/16÷(-3/16)+1
=5/16.16/-3+1
=-5/3+1
=-2/3
f)(7-3và4/5).3và1/8-1và3/5÷(0,5)^2
=(7-19/5).25/8-8/5÷1/4
=(35/5-19/5).25/8-8/5.4
=16/5.25/8-32/5
=10-32/5
=50/5-32/5
=18/5
Bài 2:
a)-17/30-11/-15+(-7/12)
=-17/30+11/15-7/12
=-17/30+22/30-7/12
=5/30-7/12
=1/6-7/12
=2/12-7/12
=-5/12
b)-5/9+5/9÷(1và2/3-2và1/12)
=-5/9+5/9÷(5/3-25/12)
=-5/9+5/9÷(20/12-25/12)
=-5/9+5/9÷(-5/12)
=-5/9+5/9.(-12/5)
=-5/9+(-4/3)
=-5/9-4/3
=-5/9-12/9
=-17/9
c)-7/25.11/13+(-7/25).2/13-18/25
=(-7/25).(11/13+2/13)-18/25
=(-7/25).13/13-18/25
=-7/25-18/25
=-25/25
=1
d)37/35
CHÚC BẠN HOK TỐT(CÂU D BÀI 2 MK KO KỊP LÀM VÌ BẬN ĐI HỌC)
THÔNG CẢM>~<
