divmod_each.rb

def div_each(r)
    b = []
    p = [10_000, 5_000, 2_000, 1_000, 500, 100, 50, 10, 5, 1]
    p.each_with_index{|d, index|
        a, r = r.divmod(d)
        b << a
        b << r if p.size - 1 == index
    }
    return b
end

p div_each(123_456) # [12, 0, 1, 1, 0, 4, 1, 0, 1, 1, 0]