vb是什么意思??
数学方式应该这样!!
设数之和为m
则m=3+6+9+···+93+96+99
所以m=99+96+93+···+9+6+3
那么2m=102+102+102···+102
因为100中有33个数能整除3
所以2m=102*33
所以m=51*33
Private Sub Command1_Click()
Dim i As Integer, n As Integer
For i = 300 To 400
If i Mod 3 = 0 Then n = n + 1
Next
Print n
End Sub