manipulate the result of two oid

[betobaracho]

I would like to manipulate the outcome of two samples as follows:
a given oid tells me the number of dropped packets on the interface.
a secundo oid tells me the total number of packets moving through the interface.
I would like to manipulate the results can for example divide them to obtain the percentage of packets discarded.

can someone give me a hint?
I thank you.

[gandalf]

Yep. Create a graph that uses both data sources. Then, please create a CDEF that does the math. See CDEF chapter at the 1st link of my sig.
R.

[betobaracho]

thanks