Tính nhanh A=(1+1/3+1/5+1/7+...+1/97+1/99).1/5/ 2/1.99+2/3.97+...+2/49.51.
Tính nhanh A=(1+13+15+17+...+197+199).1521.99+23.97+...+249.51 .
Ta có: A=(1+13+15+17+...+197+199).1521.99+23.97+...+249.51
A=(1+199)+(13+197)+...+(149+151)5(21.99+23.97+...+249.51)
A=10099.1+1003.97+...+10049.5110(11.99+13.97+...+149.51)
A=100(199.1+13.97+...+149.51)10(11.99+13.97+...+149.51)
A=10010=10.