Can I calculate the average of these numbers?

int currentCount = 12;
float currentScore = 6.1123   (this is a range of 1 <-> 10).

int currentCount now equals 13
float currentScore now equals ?????

currentScore = (currentScore * currentCount + newValue) / (currentCount + 1)
currentCount = currentCount + 1

+--------+-------+----------------------+----------------------+
| Number | Count |   Actual average     | Calculated average   |
+--------+-------+----------------------+----------------------+
|      7 |     1 | (7)/1           =  7 | (0 * 0 +  7) / 1 = 7 |
|      9 |     2 | (7+9)/2         =  8 | (7 * 1 +  9) / 2 = 8 |
|     11 |     3 | (7+9+11)/3      =  9 | (8 * 2 + 11) / 3 = 9 |
|      1 |     4 | (7+9+11+1)/4    =  7 | (9 * 3 +  1) / 4 = 7 |
|     12 |     5 | (7+9+11+1+12)/5 =  8 | (7 * 4 + 12) / 5 = 8 |
+--------+-------+----------------------+----------------------+

current_sum += input;
current_count++;
current_average = current_sum/current_count;

newScore = (currentScore * currentCount + someNewValue)/(currentCount + 1)

current_average = (current_sum = current_sum + newValue) / ++current_count;