Xiaoming is making cookies. Each batch of cookies uses 3 eggs. If Xiaoming has 20 eggs, and assuming he has enough of the other ingredients to make the cookies, what is the greatest number of batches that he can make?

If Xiaoming has 20 eggs, and each batch of cookies uses 3 eggs, the number of batches can be found by dividing 20 by 3. This does not divide evenly, so the number should be rounded down to 6 because Xiaoming does not have enough eggs to make 7 (3 × 3 eggs) batches (7 × 3 = 21).
3 is incorrect because 3 batches would use only 9 eggs . This means that Xiaoming would have 11 eggs left, which is enough to make more batches. 7 is incorrect because 7 batches would use 21 eggs (3 × 7 = 21), but Xiaoming has only 20 eggs. 17 is incorrect because 17 batches would use 51 eggs (17 × 3 = 51), but Xiaoming has only 20 eggs.