import re
text = "४०० pounds of wheat at $ 3 per pound"
matches = re.findall(r'(\d+(?:[.,]\d+)*)(?:\s*(\w+))?', text)
print( [(x, y) for x, y in matches] )
aW1wb3J0IHJlCnRleHQgPSAi4KWq4KWm4KWmIHBvdW5kcyBvZiB3aGVhdCBhdCAkIDMgcGVyIHBvdW5kIgptYXRjaGVzID0gcmUuZmluZGFsbChyJyhcZCsoPzpbLixdXGQrKSopKD86XHMqKFx3KykpPycsIHRleHQpCnByaW50KCBbKHgsIHkpIGZvciB4LCB5IGluIG1hdGNoZXNdICk=