There is no need to disrupt your flow in your client meeting by jumping to another application, losing the train of thought and the interest of your clients.
Check out this 1' 45" demonstration:
A simple calculator is built into every dollar value field.
Click into a dollar value field (Asset-Map or Target-Map) and start your formula with an equals sign ("=") . Then enter your formula and click the "Enter" (Return) key on your keyboard for the result.
Tags: add, subtract, multiple, divide, calculate, calculator, numbers, values.