Respuesta :
you can use gauss's method
n(first number + last number)/2 where n is the number of integers in this case 21 ()
21(0.30 + 0.50)/2
21*0.8/2
21*0.4
8.4
n(first number + last number)/2 where n is the number of integers in this case 21 ()
21(0.30 + 0.50)/2
21*0.8/2
21*0.4
8.4