Help whats problem of my code . In No numerals

Question

Problem in test case 3,4,5

txt = str(input()).lower()

def No(text):
Numerals = {
"1": "one","2": "two","3":"three","4": "four",
"5": "five","6": "six","7": "seven","8":"eight","9": "nine","10": "ten",
"0": "zero"
}

temp = []
txt = list(text)
for i in txt:
num = i.isnumeric()
if num == True:
temp.append(Numerals[i])
else:
temp.append(i)

print("".join(temp))

No(txt);

Answer 1

10 is read as 1 and 0 instead of 10 so you get "one zero" as output if there is 10 in inputted string
Change ,
for i in txt to => for i in txt.split()

Answer 2

Same result i change the value under 10 and change the expression of for loop but the error is the same.
Failed in case 3,4,5