Working with Units in Wolfram Mathematica

Questions
1

Hello,

How can I do this in Wolfram Mathematica?
How can I work with units of measurement in Wolfram Mathematica?

Capture4.JPG
Capture4.JPG242×231 8.44 KB

Thank you.

2

Something like this?

i1 = Quantity[2, "Amperes"]
i2 = Quantity[5, "Amperes"]
i1 + i2

UnitConvert[i1 + i2, "Milliamperes"]
UnitConvert[i1 + i2, "Microamperes"]