You can't "work out" 9 volts and 0.02 amps in the same way you might work out a math problem. Those are specific values for voltage and current, respectively, which are two fundamental electrical quantities.

Here's what you need to know:

* Voltage (V): Measures the electrical potential difference between two points. It's like the "pressure" that drives the flow of electricity.

* Current (I): Measures the rate of flow of electrical charge. It's like the "amount" of electricity flowing.

Relationship:

The relationship between voltage and current is defined by Ohm's Law:

* V = I * R

Where:

* V = voltage (in volts)

* I = current (in amps)

* R = resistance (in ohms)

What you can do with 9 volts and 0.02 amps:

If you know the voltage and current, you can calculate the resistance using Ohm's Law:

* R = V / I = 9 volts / 0.02 amps = 450 ohms

Therefore, knowing the voltage and current allows you to understand the resistance of the circuit or device.