The voltmeter uses a range of 0 ~ 3V, with each large battery representing 1V and each small battery representing 0. 1V, and the voltage is 2.6V 。

The ammeter uses a range of 0 ~ 0.6A, each large battery represents 0.2A, each small battery represents 0.02A, and the current is 0.26A. 。

r = UI = 2.6v 0.26 a = 10ω。

So the answer is: 2.6; 0.26; 10.