Tiny calculator on Python 3

Question

Hi, wrote some code, please advice how this idea can be optimized (less code, DRY). I'm just studing the Python, so know very little...)
import re
while True:
while True:
i = input('1st number: ')
pattern = r"[0-9]"
if re.search(pattern, i):
break
else:
print('Only numbers allowed. ')
while True:
j = input('Choose + - * / as operator: ')
if j in ['+', '-', '*', '/']:
break
else:
print('Invalid operator. Try + - * / ')
while True:
k = input('2nd number: ')
pattern = r"[0-9]"
if re.search(pattern, k):
if k == '0' and j == '/':
print('No division by zero. ')
else:
break
else:
print('Only numbers allowed. ')
d = eval(i + j + k)
print('Result:', d, '\n')
print('=' * 7)

Answer 1

Example
99/2*5
https://code.sololearn.com/ck9rtCKNCAdK/?ref=app

Answer 2

For checking if it's only digits you don't need 're'. Just take this string method:
string.isdigit()

Answer 3

You are asking for a number two times. I would consider writing a function that returns a number that was given by the user.
For example:
def number():
while True:
number = input()
if number in [str(n) for n in
range(10)]:
return int(number)
Then you can just call this function two times:
x=number()
y=number()

Answer 4

wondering if I could shorten 'while' cycle...

Answer 5

Mates, thank yor for help!
Here's some new iteration:
=========
while 1:
try:
a, b, c = input ('Enter mathematical task with _spaces_\nExample: 2 + 9: '). split ()
d = eval(a + b + c)
except ZeroDivisionError:
print('Do not divide by zero.\n')
continue
except Exception as err:
print('Error. Please use spaces and digits.\n')
continue
else:
print('Result:', d, '\n')
=========
UPD: have no idea how enforce user's input to add spaces...