I'm trying to do a little testing of the number_to_currency method, but no matter how I try and call it in the console I'm out of luck it seems.
ActionView::Helpers::NumberHelper::number_to_currency 12321334543.00
# => NoMethodError: undefined method `number_to_currency' for ActionView::Helpers::NumberHelper:Module
This may qualify as a duplicate, I am not entirely sure. The other question is a lot broader in scope, and therefore has a lot more ways of getting things gone presented in the answers, and I also believe it may have some outdated answers.