Multiplying two netcdf files in Python

I am new to python struggeling with loops. I would like to multiply two netCDF files within a loop. My first netcdf file contains my variables for latitude, longitude and a few variables to plot.

dimensions:
longitude = 192 ;
latitude = 145 ;
surface = 1 ;
pseudo = 13 ;
pseudo_1 = 17 ;
t = UNLIMITED ; // (156 currently)
variables:
float longitude(longitude) ;
    longitude:standard_name = "longitude" ;
    longitude:long_name = "longitude" ;
    longitude:units = "degrees_east" ;
    longitude:axis = "X" ;
float latitude(latitude) ;
    latitude:standard_name = "latitude" ;
    latitude:long_name = "latitude" ;
    latitude:units = "degrees_north" ;
    latitude:axis = "Y" ;
float surface(surface) ;
    surface:long_name = "Surface" ;
    surface:units = "level" ;
    surface:positive = "up" ;
    surface:axis = "Z" ;
float pseudo(pseudo) ;
    pseudo:long_name = "pseudo" ;
    pseudo:units = "level" ;
    pseudo:positive = "up" ;
    pseudo:axis = "Z" ;
float pseudo_1(pseudo_1) ;
    pseudo_1:long_name = "pseudo" ;
    pseudo_1:units = "level" ;
    pseudo_1:positive = "up" ;
    pseudo_1:axis = "Z" ;
double t(t) ;
    t:standard_name = "time" ;
    t:long_name = "t" ;
    t:units = "days since 1850-01-01 00:00:00" ;
    t:calendar = "standard" ;
float field1388(t, surface, latitude, longitude) ;
    field1388:long_name = "Gross Primary Productivity" ;
    field1388:units = " " ;
    field1388:_FillValue = 2.e+20f ;
    field1388:missing_value = 2.e+20f ;
    field1388:source = "Unified Model Output (Vn 7.3):" ;
    field1388:name = "field1388" ;
    field1388:title = "Gross Primary Productivity" ;
    field1388:date = "01/01/50" ;
    field1388:time = "00:00" ;`enter code here`

My second netCDF file is as follows:

dimensions:
lat = 145 ;
lon = 192 ;
variables:
float grid_area(lat, lon) ;
    grid_area:units = "m2" ;
    grid_area:long_name = "Area for each grid cell" ;
    grid_area:_FillValue = -999.f ;

I would like to multiply them to cancel out the units. I now have to find a loop where I multiply each variable in my first dataset with each value in my second dataset for each year. Can anyone help?