If you choose a divide by 10, the display will be easy to read, and all you do then is move the decimal point 1 place to the right, either in your head or if you display permits modification. You might even add a small led as a new decimal place and put it, as well as the pin for the existing decimal point, on a spdt switch. Depending on what signals you are measuring will govern the type of divider circuit ( correct term is prescaler) you will require ( nmos, ecl etc.). Digital signals are easily read, however low power rf signals, or unbuffered xtal oscillator test points will most likely need an RF amp front end with agc (automatic gain control) to reduce loading and signal variance. Some simple front end circuits can be found in the Amateur Radio Handbook, they also should have prescaler circuits for frequency counters.