To find the probability of getting a sum of 10 or 11 when two dice are thrown, we proceed as follows:
Step 1: Total number of outcomes
When two dice are thrown, each die has 6 possible outcomes. Thus, the total number of outcomes is:
\[
6 \times 6 = 36.
\]
Step 2: Count favorable outcomes for sum = 10
The combinations of values on the two dice that result in a sum of 10 are:
\[
(4, 6), \quad (5, 5), \quad (6, 4).
\]
Thus, there are 3 favorable outcomes for a sum of 10.
Step 3: Count favorable outcomes for sum = 11
The combinations of values on the two dice that result in a sum of 11 are:
\[
(5, 6), \quad (6, 5).
\]
Thus, there are 2 favorable outcomes for a sum of 11.
Step 4: Total favorable outcomes
The total number of favorable outcomes for a sum of 10 or 11 is:
\[
3 + 2 = 5.
\]
Step 5: Compute the probability
The probability \( P \) of getting a sum of 10 or 11 is:
\[
P = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} = \frac{5}{36}.
\]
Final Answer:
\[
\boxed{\frac{5}{36}}
\]