1 + 1 +1 +1 + 1 + 1 + 1 + 1 + 1 + 2 + 3 + 4 +1
= 1 x 9 + ( 2+ 3 + 4 + 1 )
= 9 + 10
= 19
1 + 1 +1 +1 + 1 + 1 + 1 + 1 + 1 + 2 + 3 + 4 +1
= 1 x 9 + ( 2+ 3 + 4 + 1 )
= 9 + 10
= 19
c) 6 1/7 + 1/7 + 1/7 + 7 1/7 d) 12 1/3 : 1/4 + 3 2/3 : 1/4 e) (1 + 1/2 ) × (1 + 1/3 ) × (1 + 1/4 ) × … × (1 + 1/2020 ) f) 1 1/2 × 1 1/3 × 1 1/4 × 1 1/5 × … × 1 1/2021
P=1/1+2+1/1+2+3+1/1+2+3+4+1/1+2+3+4+...+1/1+2+3+4+...+2018
(1+1 1/4+1 1/2+1 3/4+2+2 1/4+2 1/2+2 3/4+...+4 3/4):23
1. Q = 1/1+2 + 1/1+2+3 +1/1+2+3+4 + ............. + 1/1+1+3+4+...+10
2. 1/1 +1/3 +1/6 +1/10 + 1/15 + ... +1/x*{x+1} :2
tính nhanh
A = 1/1+2 +1/1+2+3 +1/1+2+3+4+...+...+...+1/1+2+3+4+...+2009
A = 1+1/2+1/4+1/8+...+1/4096+1/8192
A= (1/1+2)+(1/1+2+3)+(1/1+2+3+4)+(1/1+2+3+4+5)+(1/1+2+3+4+5+6)
Tìm A
1/1*2 +1/2*3 +1/3*4 + 1/4*5 +...+1/n*(n+1) 3/1*2+3/2*3+3/3*4+3/4*5+...+3/n*(n+1) tính tổng nha các bạn
Hãy điền dấu phép tính và dấu ngoặc để có: a) 1 2 3 = 1; b) 1 2 3 4 = 1; c) 1 2 3 4 5 = 1; d) 1 2 3 4 5 6 = 1; e) 1 2 3 4 5 6 7 = 1; f) 1 2 3 4 5 6 7 8 = 1; g) 1 2 3 4 5 6 7 8 9 = 1.
Cho dãy phân số sau đây:
1/1, 2/1, 1/2, 3/1, 2/2, 1/3, 4/1, 3/2, 2/3, 1/4, 5/1, 4/2, 3/3, ...
