public static bool IsNumeric(this Type dataType)
{
        if (dataType == null)
            throw new ArgumentNullException("dataType");

        return (dataType == typeof(int)
                || dataType == typeof(double)
                || dataType == typeof(long)
                || dataType == typeof(short)
                || dataType == typeof(float)
                || dataType == typeof(Int16)
                || dataType == typeof(Int32)
                || dataType == typeof(Int64)
                || dataType == typeof(uint)
                || dataType == typeof(UInt16)
                || dataType == typeof(UInt32)
                || dataType == typeof(UInt64)
                || dataType == typeof(sbyte)
                || dataType == typeof(Single)
               );
}

public static bool IsNumericType(this Type o)
{
        return !o.IsClass !o.IsInterface o.GetInterfaces().Any(q => q == typeof(IFormattable));
}

public static bool IsNullableNumericType(this Type o)
{
        if (!o.Name.StartsWith("Nullable")) return false;
        return o.GetGenericArguments()[0].IsNumericType();
}