I think an OTA (Operation Transconductance Amplifier, http://en.wikipedia.org/wiki/Operational_transconductance_amplifier) can do does at least the multiplication part of what you want, but it is far from a one-chip solution to your problem. Division of voltages seems to be a hard problem (and searching is difficult because the term 'voltage divider' means something else!). One approach would be conversion to a log scale, substracting, and conversion back to linear.
If your application involves just divisions and multiplactions it might be an idea to do everything in the log domain, convert ony at the inputs and outputs.
An example of an OTA is the LM13700 (http://www.ti.com/lit/ds/symlink/lm13700.pdf): two differential voltage inputs, and one current input that sets the transconductanes (== the multiplication factor), and the output is a current.
You did not state the accuracy, speed, range, etc you need. Within ceratin limits a microcontroller with 4 A/D inputs and one D/A output would do the trick nicely.