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a: =6/12*7/14*8/16*9/18=1/2*1/2*1/2*1/2=1/16
b: =4/12*15/3*9/25*24/8
=1/3*3*5*9/25=9/5
a) 1/2
b) 18/17; 17/16; 16/15; 15/14; 14/13; 13/12; 10/9
Nhớ k cho mk nha
a)1/2
b)Vì 18/17 <17/16 <16/15<15/14< 14/13< 13/12< 10/9
Nên, ta có:
18/17; 17/16; 16/15; 15/14; 14/13; 13/12; 10/9.
\(\dfrac{5}{15}+\dfrac{48}{16}=\dfrac{1}{3}+3=\dfrac{1}{3}+\dfrac{9}{3}=\dfrac{10}{3}\)
\(\dfrac{6}{9}:\dfrac{12}{36}=\dfrac{2}{3}:\dfrac{1}{3}=\dfrac{2}{3}\times\dfrac{3}{1}=\dfrac{6}{3}=2\)
\(\dfrac{4}{12}\times\dfrac{56}{14}=\dfrac{1}{3}\times4=\dfrac{4}{3}\)
1+(2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17)x0,000001
=1+(2+(3+17x10)+10)x0,000001
=1+(2+200+10)x0,000001
=1+212x0,000001
=1+0,000212
=1,000212
1+2-3-4+5+6-...+301+302
đặt A=(1+2)+(5+6)+...+(301+302)=3+11+19+...+603
A=[(603-3):8+1]x(603+3)=75x606=45450
đặt B=-3-4-7-8-11-13-...-299-300
B=(-3-4)+(-7-8)+(-11-12)+..+(-299-300)
B=-(7+15+23+...+599)
B=-[(599-7):8+1]x(599+7)=45450
ta có:
1+2-3-4+5+6-7-8+...+301+302=A-B=45450-45450=0
=(1+19)+(2+18)+(3+17)+(4+16)+(5+15)+(6+14)+(7+13)+(8+12)+(9+11)+10+20
=20x10+10
=210
1+2+3+4+5+6+7+8+9+10+11+12+13+14+15+16+17+18+19+20=210 nha bn