For a list of numbers 1 2 3 4 5 6 7 8 9, add operators '+', '-', or none among them, to create an albegraic expression that evaluates to sum of 110.

permutate_expr_sum.py

#!/usr/bin/python
# vim: set ts=4 sts=4 et fileencoding=utf-8:

import itertools
target = 110
ops = [' + ', ' - ', '']
digit_list = list('123456789')
for op_list in itertools.product(ops, repeat=8):
    expr = ''.join([ item for pair in zip(digit_list, op_list + ('',)) for item in pair ])
    try:
        if eval(expr) == target: print "%s = %d" % (expr, target)
    except: pass

## From CCF.