Reindex the Applications folder for Spotlight:
1. Navigate to > System Preferences > Spotlight.
2. Click the Privacy tab.
3. Click the Add button and select the Applications folder or drag it to the list.
4. Click to highlight the Applications folder you just added.
5. Click the minus button to remove the Applications folder from the list.
6. Close System Preferences.
Spotlight will begin reindexing the Applications folder.
Two observations:
1. Spotlight, more often than not, will present as the Top Hit an app selected most often. In some cases I only need type one letter, even though more than one app begins with that letter.
2. If I start typing the first two letters of Calculator (ca), "calendar" will display. On the very next letter typed (l), Spotlight will display "calculator" as if to say "OK, you didn't like my first suggestion, how about this one", even though "cal" forms the first three letters of both applications. Consequently, I've gotten in to the habit of typing fewer letters. As a suggestion, you might start typing "cal" instead of "calc" to make Calculator the Top Hit if Calendar displays first.
