tinh tong s=1*100+2*99+3*98+..+49*51+50*50
bai1:tinh tong S=1.3+3.5+5.7+...+99.101
bai2 :tinh tong S=1.4+4.7+7.10+...+2017.2020
bai 3: tinh tong N=2.4+4.6+6.8+..+100.102
bai 4: tinh tóng=2.6+6.10+10.14+14.18+...+42.46+50.54
bai 5:tinh tongB=2^2+4^2+6^2+...+100^2
bai 6:C=1^2+3^2+...+100^2
bai7: biet 1^2+2^2+3^2+...+10^2=385 tinh tong 2^2+4^2+6^2+...+20^2
bai 8: tinh tong s=1^2+2^2+3^2+...+99^2
tinh tong
a)s=1+(-2)+3+(-4)+.......+2009+(-2010)
b)s=1+(-2)+(-3)+4+5+6(-6)+(-7)+......+2008+2009+(-2010)
Tinh tong S = 1×2+2×3+3×4+4×5+•••••+99×100
TINH TONG:
S=1+2-3-4+5+6-7-8+....-2005-2006+2007+2008
1.Cho tong S=5+8+11+14...
tim so hang thu 100 cua day
2.Tinh tong S=1+2+22+...+210
tinh tong :S=1-2+3-4+5-6+...+2015-2016
tinh tong s=1/2^2+1/3^2+...+ 1/10^2
Cho: S=1/2+1/3+.+1/30, P=1/49+2/48+..+48/2+49/1. Tinh S/P
