Is 700c 25/32 iner tubes the same as 700c 18/25? I'm trying to replace inner tubes on my bike but I got ones that do not match the one that I am taking out of a wheel.
700 essentially refers to the diameter of the wheel, while the other two numbers give the range of tyre widths that the tube is suitable for. So 18-25 covers tyres between 18mm and 25 mm inclusive, while 25-32 would suit slightly wider tyres (25mm wide - 32mm wide inclusive) of the same wheel diameter. 

So both tubes would suit a 700c x25 tyre as they overlap sizes there, but they aren’t the same per se