What would the formula be to work this out

I have 3 values, which are:

560
500
-156

560 happens 21.3% of the time
500 happens 19.8% of the time
-156 happens 58.9% of the time

With a total range of 716, how would I work out what the single average value is, using those percentages?

For example, if I had values of:

1000
0

1000 happened 50% of the time, and
0 happened 50% of the time,

the average value, using those percentages would be 500.

If 1000 happened 75% of the time, and
0 happened 25% of the time,

the average value using those percentages would be 750.

Here you would find the weighted average.

Multiply each number by its decimal percentage, and add them together.

1000*(.50) = 500
0 * (.5) = 0
500 + 0 = 500

1000*(.75) = 750
0*(.25) = 0
1000 + 0 = 1000

560(.213) = 119.28
500(.198) = 99
-156(.589) = -91.884

119.28 + 99 - 91.884 = 126.396