tính bằng cách hợp lí nhất
1/1*2+1/2*3+1/3*4+......+1/99*100+1/100*101
3/5*8+3/8*11+3/11*14+.........3/605*608+3/608*611
Tính nhanh
1/8*11 +1/11*14 +.....1/605*608=?
Tính nhanh :
1 / 8 x 11 +1 / 11 x 14 + 1 /14 x 17 + ... + 1 / 602 x 605 + 1 / 605 x 608
\(\frac{3}{5\times8}+\frac{3}{8\times11}+\frac{3}{11\times14}+.........+\frac{3}{605\times608}+\frac{3}{608\times611}\)
\(\frac{3}{5\times8}+\frac{3}{8\times11}+\frac{3}{11\times14}+...+\frac{3}{605\times608}+\frac{3}{608\times611}\)
3/5*8+3/8*11+3/11*14+.....+3/602*605
tính A= 1/8*11+1/11*14+...+1/605*608
A=1/8*11+1/11*14+...+1/605*608. Tính A.
tính tổng sau:A= 1/8*11+1/11*14+........+1/605*608
