Quiz Contest # 13

Quiz Contest and win 0.10 sbd by simple math solution.

Question: What number will sit in Empty space?

Rules:

1. Resteem and upvote this post.
2. Write Your Answer in comment.
3. If correct answer is more than one.. then winner (only one) will be select by Lottery.

source: create by me

Participate Quiz Contest and win 0.10 sbd. You will earn 0.10 SBD and offer is valid for 7 days.
thanks.