What does it mean to assign a value to a variable?

In score = score + 5, beginners may think score is used twice at once. Actually the old value is read first, then the new value is stored. For example, if score is 10, the right side becomes 10 + 5 = 15, and then score becomes 15. The name on the left is not read until the store happens. This two-step process is key. 15

Assignment means linking a name to a value, like score = 10, and it changes the program's state. Remember: read the right side first, then store the result in the name on the left. For example, score = score + 5 uses the old value to make a new one. This simple idea is the foundation of how programs keep track of data. 16