4. In a box, there are a thousand balls numbered $1,2,3, \ldots, 999,1000$. What is the probability that a number drawn in one draw is not divisible by either 4 or 6? Write the solution as a percentage.
## 4. First Method:

The total number of balls is 1000.

Among the first 1000 natural numbers, there are 250 divisible by 4, 1 POINT

and 166 divisible by 6. 1 POINT

However, there are numbers that are divisible by both 4 and 6.

These are multiples of 12. There are 83 of them.

1 POINT

Therefore, the total number of numbers that are not divisible by either 4 or 6 is

$1000-250-166+83=667$.

2 POINTS

(Or:

The total number of numbers that are divisible by 4 or 6 is $250+166-83=333$.

1 POINT

The number of numbers that are not divisible by either 4 or 6 is $1000-333=667$.

1 POINT)

The desired probability is $\frac{667}{1000}=66.7 \%$