Type the missing digit:
4 | , | 2 | 1 | ||
| + | 2 | , | 3 | 5 | 0 |
7 | , | 2 | 7 | 1 |
ref_doc_title.
Jumping to level 1 of 1
Excellent!
Now entering the Challenge Zone—are you ready?
4 | , | 2 | 1 | ||
| + | 2 | , | 3 | 5 | 0 |
7 | , | 2 | 7 | 1 |
Now entering the Challenge Zone—are you ready?