Các câu hỏi tương tự
1/1+2+1/2+3+1/3+4+...+1/98+99+1/99+100
CMR
100-(1/2+1/3+1/4+...+1/100)=2/3+3/4+...+99/100
A = 1-2+3-4+5-6+.....+97-98+99-100+101
B = 1+2-3-4+5+6-7-8+......+98-99-100+101
(1-1/2)×(1-2/3)×(1-3/4)×......×(1-99/100
Tính nhanh
a,(1+2 +3 +...+99) x (13 x 15 – 12 x 15 –15)
b,2+4+ 6+...+ 98+100–(1+3 +5 +...+97+99)
tính: 1 * 2 + 2 * 3 + 3 * 4 + ......+ 99 * 100
a) S= 1/1*2 + 1/2*3 + 1/3*4 + ...............+ 1/99*100
tính tổng :S = 1/1*2 + 1/2*3 + 1/3*4 + 1/4*5 + .........+ 1/99*100
1)Tính:
a)100-99+98-97+.............+4-3+2-1
b)99-97+95-93+...............+7-5+3-1