Add value from a helper to another helper

I have a helper ‘input_number.car_charger_ampere’, with allowed values from 5 to 32.

Dit value is increased or decreased with a node, that works.
Now I want to create a node, that adds the value of another helper called ‘input_number.max_powercharge_current’ to the helper ‘input_number.car_charger_ampere’

Why ?

I’m controlling my EV charger over modbus, and I’m able to set the current according to the solar panels power.
BUT, sometimes I want to charge faster, so I have a slider (max_powercharge_current) that sets the max current to be drawn from the net, so that value has to be added to the current value from the solar panels.