Answer:
2
Step-by-step explanation:
The last number is 2
You calculate this by the only way the mean can be 4 is if the 3 numbers= up to 12. so 9 + 1=10 and if were looking for 12 we need 2 more so 2.
10 + 2=12
When dealing with mean you calculate the sum of all the number(check) then divided by the total of numbers so 3
12 divided by 3=4 and 4= your mean
Hope it helps have a great day:)
