$ perl examples/bc/bc5.pl
examples/bc/bc5.pl.out
1..10
ok 1 - warranty
ok 2 - echo
ok 3 - numbers received
ok 4 - expected value of 23+7
ok 5 - echo
ok 6 - numbers received
not ok 7 - expected value of 11+1
#   Failed test 'expected value of 11+1'
#   at examples/bc/bc5.pl line 29.
#          got: '12'
#     expected: '10'
ok 8 - echo
ok 9 - numbers received
ok 10 - expected value of 2*21
# Looks like you failed 1 test of 10.