Option Explicit
Sub abc()
Dim a, i, j, sum
a = [a1].CurrentRegion.Resize(, 1).Value
ReDim b(1 To UBound(a), 1 To 3)
For i = 1 To UBound(a)
sum = a(i, 1)
For j = 1 To 2
b(i, j) = (CLng(Rnd * 7) + 27) / 10
sum = sum - b(i, j)
If j = 2 Then
If sum >= 2.7 And sum <= 3.3 Then
b(i, j + 1) = sum
Else
sum = a(i, 1): j = 0
End If
End If
Next
Next
[c1].Resize(UBound(b), 3) = b
End Sub