$ cat bench.py 
from timeit import timeit as bench

print('+', bench('222223092812821217777777776361299889812878712817211212177362 + 37625362718291047364361661261819210'))
print('-', bench('222223092812821217777777776361299889812878712817211212177362 - 37625362718291047364361661261819210'))

$ cat bench.scm 
(use numbers)

(define a 222223092812821217777777776361299889812878712817211212177362)
(define b 37625362718291047364361661261819210)

(define (bench op)
  (display op)
  (display " ")
  (time
   (let ((x 0))
     (let loop ((i 1000000))
       (unless (fx= 0 i)
         (op a b)
         (loop (fx- i 1)))))))

(bench +)
(bench -)

$ python bench.py && csi -s bench.scm 
('+', 0.02112102508544922)
('-', 0.021150827407836914)
#<procedure (numbers#+ . args236)> 0.712s CPU time, 0.148s GC time (major), 16 mutations, 62/3177 GCs (major/minor)
#<procedure (numbers#- arg1281 . args282)> 0.508s CPU time, 0.012s GC time (major), 16 mutations, 5/3219 GCs (major/minor)