Answer:
10,000
Step-by-step explanation:
This is how I know:
1. Using 800+10 we get the amount of 810.
2. Take away 810 from 10,810 and you get 10,000.
3. Now we know that 10,000 is the missing number because adding 10,000 to 810 would give us 10,810 which is what ? + 800 +10 is equal to.
I hope this helps:)
