Confirming what Pinkus said.
I hooked a Maynuo M9712 to a power supply and set the power supply for 1 V and 0.5 A and then tried various combinations of settings on the Maynuo, such as varying the I, R, and P settings while the Maynuo was powered on and the on/off button was engaged (on). Using the rotary encoder you can move up and down the decimal places by pushing the encoder dial in (it makes a click sound to confirm as you change decimal places). At each decimal place you can then turn the rotary encoder up or down to change the values 0-9 and with each change while everything is live (power supply and load are both in their "on" states), you can see the values change accordingly: the voltage and current show on my power supply and VIRP change on the Maynuo.
One small thing to remember on the Maynuo is that when you change settings (V,I,R, or P) when you first go into the setting you first have to hit a keypad number. Say, you are on current, you first hit a 1 and it will give you a 1.000000 displayed value, or you hit a .1 and it will give you a 0.100000 value. Once the first value has been keyed in with a keypad number depress, the rotary encoder can then be invoked to either go up or down in that decimal column with a turn of the knob, or with a depress of the knob you can then move up and down the decimal places, and then turn the knob within that place. You can go in and out of places and up and down in each decimal place easily and quickly, you just have to remember to enter a full number value from the keypad to tell it you are serious about changing a value each time you select a particular setting. Each setting has it's own dedicated button (V-set, I-set, R-set, P-set).
It's really a great piece of equipment. I don't use it as often as I should but every time I use it I'm reminded of how flexible and useful it is. I can't prove it but I have a hunch it's pretty accurate and it has a lot resolution (6 digits to the right of the decimal on each setting). While it's probably too pricey to be just a learning tool I can't think of a better way for a new electronics enthusiast to see the immediate relationships between all four components of Ohm's Law. Just connect it to a power supply and change the values on either the power supply or the Maynuo and watch which direction everything goes until you see the value relationships - both on the Maynuo and the power supply (if it has readouts). In addition to seeing the values change you will see the power supply and the Maynuo reflect whether you have gone into constant current or constant voltage; on the Manynuo it has a readout that says CV or CI or CR or CW, or Unreg if you reach an unregulated state. It's pretty cool.
So, yes, I think it does what you are asking about. If you have a combination of values you want me to try let me know and I'll give it a whirl.