tinh bang cach hop li :
2003 nhan 2005 +200 /2004 nhan 2004 +199
Tính bằng cách thuận tiện nhất :
2003×2005+200
2004×2004+199
2003×2005+200 = 4016215
2004×2004+199 = 4016215
1)2003x2005+200 2)2004x2004+199
=(200x10+3)x2005+200 =2004x2004+(200-1)
=200x10x2005+3x2005+200 =2004x2004+200-1
=200x(10x2005+1)+3x2005 =(200x10+4)x2004+200-1
=200x20051+6015 =200x10x2004+4x2004+200-1
=4010200+6015 =200x(10x2004+1)+4x2004-1
=4016215 =200x20041+8016-1
=4008200+8015 =4016215
chọn mình nha
Tính bằng cách thuận tiện
2003*2005+200
2004*2004+199
\(\frac{2003\cdot2005+200}{2004\cdot2004+199}\)= \(\frac{4016015+200}{4016016+199}\) = \(\frac{4016215}{4016215}\) = 1
Chúc bạn Hk tốt!!!!!
tính bằng cách thuận tiện nhất :
2003 x 2005 + 200
2004 x 2004 + 199
2003x2005+200=4016215
2004x2004+199=4016215
so sanh cac phan so sau bang cach hop ly
2005/2007va20007/2005 2010/2007va2007/2004
2003/2004+2004/2005+2005/2003 va 3[ so sanh ] cac ban lam cach ngan gon de hieu nhe
\(\frac{2003}{2004}+\frac{2004}{2005}+\frac{2005}{2003}=1-\frac{1}{2004}+1-\frac{1}{2005}+1+\frac{2}{2003}\)
\(=3+\left(\frac{1}{2003}-\frac{1}{2004}\right)+\left(\frac{1}{2003}-\frac{1}{2005}\right)\)
Do \(\frac{1}{2003}>\frac{1}{2004}>\frac{1}{2005}.\) nên \(\left(\frac{1}{2003}-\frac{1}{2004}\right)+\left(\frac{1}{2003}-\frac{1}{2005}\right)>0\)
Vì vậy \(3+\left(\frac{1}{2003}-\frac{1}{2004}\right)+\left(\frac{1}{2003}-\frac{1}{2005}\right)>3\) (đpcm)
\(A=\frac{2003}{2004}+\frac{2004}{2005}+\frac{2005}{2003}\)
\(=(1-\frac{1}{2004})+(1-\frac{1}{2005})+(1+\frac{2}{2003})\)
\(=3+(\frac{1}{2003}+\frac{1}{2003}-\frac{1}{2004}-\frac{1}{2005})\)
Do\(\frac{1}{2003}\)>\(\frac{1}{2004}\)>\(\frac{1}{2005}\)
\(\Rightarrow\frac{1}{2003}+\frac{1}{2003}+\frac{1}{2004}+\frac{1}{2005}\)>\(0\)
\(\Rightarrow3+(\frac{1}{2003}-\frac{1}{2004}+\frac{1}{2003}-\frac{1}{2005})\)>\(3\)
\(\Rightarrow A\)>\(3\)
Tinh nhanh :
a) Tu so : 2005*2007-1
Mau so : 2004+2005*2006
b) Tu so : 2003*2004+2005*10+1994
Mau so: 2005*2004-2003*2004
a) \(\frac{2005.2007-1}{2004+2005.2006}=\frac{\left(2014+1\right).2007-1}{2004+2005.2006}=\frac{2004+2005.2007-1}{2004+2005-2006}=\frac{2004+2005.2006}{2004+2005.2006}=1\)
a)Tinh nham bang cach nhan thua so nay ,chia thua so kia cho cung mot so thich hop :
14 . 50 ; 16 . 25
b)Tinh nham bang cach nhan ca so bi chia va so chia voi cung mot so thich hop :
2100 : 50 ; 1400 : 25
a) 14.50 = (14:2).(50.2) = 7.100 = 700
16.25 = (16:4).(25.4) = 4.100 = 400
b) 2100:50 = (2100.2):(50.2) = 4200:100 = 42
1400:25 = (1400.4):(25.4) = 5600:100 = 56
tính nhanh:2004 nhân 2004 cộng 1002/2004 nhân 2005 tru 1002
xin lỗi computer ko go nhan duoc
Tinh : N=2003.(20049+20048+...+20042+2005)+1