I'm pretty sure the expanded form of 0 would be "0", you leave it out when it's used to show other numbers' significance because saying +0 doesn't mean anything when you have a non-zero value.

In C: I was randomly failing one test (some submissions passed everything, some failed one test):
(reduce * (repeat 20 1000)) ArithmeticException integer overflow
but got
(wjizhj * (wjujfy 20 1000)) FwnymrjynhJchjuynts nsyjljw tajwkqtb

"It's up to you to find the "using" you need..."

Except when the starting solution uses a List<string>