5. Miss Diaz wants her students to practice making the next ten.
a. Circle the problems Miss Diaz should give her students.
\[
\begin{array}{lllll}
12+23 & 38+22 & 64+99 & 36+40 & 79+48
\end{array}
\]
b. Explain why Miss Diaz should give the problems you circled.

Step 1 ：Define the problems as pairs of numbers: \((12, 23), (38, 22), (64, 99), (36, 40), (79, 48)\)

Step 2 ：Create a function to check if the sum of the units digits of each pair is 10 or more.

Step 3 ：Apply the function to each pair of numbers.

Step 4 ：The function identifies the pairs \((38, 22), (64, 99), (79, 48)\) as the ones where the sum of the units digits is 10 or more.

Step 5 ：These are the problems that Miss Diaz should give her students to practice making the next ten.

Step 6 ：When the sum of the units digits is 10 or more, we need to carry over the value to the tens place. This is the concept of 'making the next ten'. For example, in the problem \((38, 22)\), the units digits are 8 and 2, and their sum is 10. This means we need to carry over 1 to the tens place, making the next ten. The same applies to the other two problems.

Step 7 ：Final Answer: The problems Miss Diaz should give her students are \(\boxed{(38, 22), (64, 99), (79, 48)}\). These problems are suitable because the sum of the units digits is 10 or more, which requires making the next ten.