This package allows the use of calc in regions with multiple-cursors.

Use ~M-x package-install mc-calc~ to install this package.

Use ~M-x mc-calc-eval~ to replace multiple regions with result from
evaluating in calc.

Use ~M-x mc-calc-grab~ to grab multiple regions as vector in calc and
open calc (returnable to current buffer).

Use ~M-x mc-calc~ to open calc (returnable to current buffer).

Use ~M-x mc-calc-copy-to-buffer~ to replace multiple regions
from top level vector and return to buffer.

You can customize used calc options in `mc-calc-eval-options'
and `mc-calc-major-mode-eval-options-alist'.