Thuc hien phep tinh : 2-4-6+8+10-12-14+16+...-2006+2008+2010-2012
Tinh gia tri bieu thuc
2-4-6+8+10-12-14+16+.......-2006+2008+2010-2012
1. thuc hien phep tinh
a, 2-4+6-8+...+1998-2000
b, 2-4-6+8+10-12-14+16+...+1994-1996-1998+2000
a,Ta có: 2-4+6-8+...+1998-2000 = (2-4)+(6-8)+...+(1998-2000)
=-2+-2+...+-2 (500 số -2)
=-1000
Tính
A=1-2+3+4-5-6+7+8-9-.....+2007+2008-2009-2010
B=2^2005-2^2003-2^2001-......-2-1
C=2+4+4+8+10-12-14+16+......-2006+2008+2010-2012
D=1-2-3-4+5-6-7-8+9-10-11-......-2010
Bài 1:Tính tổng :
1.D=1+3-5+7+.........+2011
2.E=2-4+6-8+..........+2006-2008+2010-2012
3.F=2-4-6+8+810-12-14+16+...................+98-200-102+104
4.H=1+2-3-4+5+6-7-8+9+10-11-12+....................-111-112+113+114
tinh tong : A=2+4-6-8+10+12-14-16+18+20-22-24+.......+2004-2006-2008
A=-2008 tick cho tớ nhé nguyen dinh chi kim kết bạn rồi nhé
Thuc hien cac phep tinh sau một cách hợp lí:
a) (10^2 + 11^2 + 12^2) : (13^2 + 14^2)
b) 1.2.3...9-1.2.3...8-1.2.3...7.8^2
c) (3.4.2^16)^2/11.2^13.4^11-16^9
d) 1152 - (374 + 1152) +(-65 + 374)
e) 13-12+11+10-9+8-7-6+5-4+3+2-1
thuc hien phep tinh bang cach nhanh nhat ( ko dung may tinh )
22^2008-2^2007-2^2006-...-2^2-2-1
Tính :
A = 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 - 11 - 12 +....+ 2006 - 2007 - 2008 + 2009 - 2010 - 2011 - 2012
b=2-4-6+8+10-12-14+16+...+2002-2004-2006+2008