What is the way to calculate the Voltage gain of cascade common-emitter BJT amplifier?
You should use \$25(\beta+1)/I_C\$ for the input impedance; the base current also flows through the emitter in addition to the collector current.

Also don't forget that the 25mV figure is an approximation for the thermal voltage; the textbook seems to be using 25mV, the same as you, but a more accurate figure is 25.85mV.