tinh tong s=1.1/2+1/2.1/3...+1/29.1/30
Tính : a) 1/100.99 - 1/99.98 - 1/98.97 - ... - 1/3.2 - 1/2.1
b) ( 1+2+3+...+100) . ( 1/3 - 1/5 - 1/7 - 1/9 ) . ( 6,3 . 12 - 21 . 3,6) / 1/2+1/3+1/4+...+1/100
Bài 1
a, 1/999.1000-1/998.999-1/998.999-1/997.998-....-1/2.1
B,(1/2^2-1).(1/3^2-1.(1/4^2-1)....(1/100^2-1)
TINH NHANH :
A= ( -1/2)-(-3/5)+(-1/9)+1/131-(-2/7)+4/35-7/18
B=1/99-1/99.98-1/98.97-...-1/4.3-1/3.2-1/2.1
Mn tính nhanh giúp mình nhé
1. 1-2+3-4+5-6-.....+99-100
2.1+3-5-7+9+11-.....-397-399
3. 1-2-3+4+5-6-7+...+96+97-98-99+100
4. 2100-299-298-......22-2-1
Tinh
a,\(C=\frac{5}{2.1}+\frac{4}{1.11}+\frac{3}{11.2}+\frac{1}{2.15}+\frac{13}{15.4}\)
b, \(S=\frac{1+2+2^2+2^3+...+2^{2015}}{1-2^{2016}}\)
Tính :
a. 1/2 + 1/3 + 1/4
b. 5/2 - 1/3 + 1/4
c. 1/2.1/3 + 1/2.2/3
d. 3/2 - 1/3 + 2/5
Không dùng máy tinh bỏ túi.Tính hợp lí:
a,4/2.4+4/4.6+4/6.8+......+4/2012.2014
b,5/2.1+4/1.11+3/11.2+1/2.15+13/15.4
c,(2/3+2/7-1/14):(-1-3/7+3/28)
d,1/10+-1/20+-1/30+-1/42+-1/56+-1/72+-1/90
tính hợp A=1/2+1/3-1/4:(1/2+1/3-1/4)-1/2.1/3.1/4