You can use various strategies such as place value understanding, mental math, or using base-10 blocks to add a 2-digit number and a 1-digit number. Practice these strategies to find what works best for you!
When adding a single digit to any given two-digit number, only the ones place changes because no new tens are added or taken away. The tens remain the same.
To reinforce your addition skills, you can practice solving more addition problems involving different combinations of two-digit numbers and one-digit numbers. You can also play math games that focus on addition.