Ah .... so you want to make a meter into a battery tester by adding a load. Well, that IS the simple way to do it - but for a valid measurement, you will need the right load for the particular battery.
Isn't 100 ohms correct for 1.5 to 9v?
The suitable resistor depends on the size of the battery. 100 Ohm is quite low for a coin cell, but quite high for a car battery.
It depends on the battery type if one needs a load resistor to test a battery.
For the alkaline cells one can get away without a load resistor, as the open circuit voltage of the cells goes down. Usually 1.2 V per cell are considered empty, as not much charge is left than. However it depends on the circuit and some work down to less than 1 V while others already complain (stop working) at 1.4 V.
Old style dry cells and Li coin cells like CR2032 need a load to get a meaningful result. When empty the open circuit still stays nearly the same, but the internal resistance goes up and the voltage thus drops under load. A those cells are usually used with light load one can use a larger resistor, like 1000 or even 10000 ohm for testing. Such a battery may be empty for circuits that need relatively high current like a flash light, but may still work for a low load like a clock.
I noticed the difference between the battery cells with an alarm clock: with a dead alkaline cell the clock stoped / slowed down but the alarm still worked till the end. With a dry cell the clock still worked, but the alarm failed when the battery was empty.