1.2+2.3+3.4+4.5+.....+97.98+98.99+99.100
tính A=1.2+2.3+3.4+4.5+.........................+98.99+99.100
Tính tổng:
A=1.2+2.3+3.4+4.5+5.6+.........+98.99+99.100
Tính nhanh :
\(\frac{2}{1.2}+\frac{2}{2.3}+\frac{2}{3.4}+\frac{2}{4.5}+\frac{2}{98.99}+\frac{2}{99.100}\)
1.2+2.3+3.4+...+98.99+99.100
B=1.2+2.3+3.4+...+98.99+99.100
1.2+2.3+3.4+4.5+...+98.99
1.2+2.3+3.4+4.5+...+98.99
Tính : A = 1.2 + 2.3 + 3.4 + ..... + 98.99 + 99.100