To determine how many cups of milk Tammy needs for 1 batch of cookies, divide the total amount of milk used by the number of batches:

$\frac{23 \, \text{cups of milk}}{13 \, \text{batches}} = \frac{23}{13} \approx 1.77 \, \text{cups of milk per batch}.$

So, Tammy needs approximately 1.77 cups of milk for 1 batch of cookies.

Would you like more details on the calculation?

Here are 5 related questions:

1. How many cups of milk would Tammy need for 5 batches of cookies?
2. If Tammy wanted to make only half a batch of cookies, how much milk would she need?
3. How many batches of cookies could Tammy make with 46 cups of milk?
4. If the recipe changes and Tammy needs 2 cups of milk per batch, how much milk would she need for 13 batches?
5. How much milk would Tammy need if she doubled the recipe for 13 batches?

Tip: When dividing fractions or decimals, always double-check if rounding is necessary depending on the context!