You may choose to display either 10 or 15 columns for assignments. The 15 column view saves space by showing only the first 4 characters of the assignment title on the gradebook speadsheet. With 10 columns you'll see the first 12 characters of the assignment title. Either way, hovering over an assignment title produces a small pop up window in which the full assignment title is displayed along with the essential assignment details.
From any page in your portal, click the Settings link (the gear icon) near the top right of the page, the select any of your gradebooks from the Gradebook Settings section of the next page. Finally, click on the Go button for Number of Columns in Gradebook.
Ten vs Fifteen Columns
10 Columns: Larger font for assignment titles
15 Columns: Smaller font for assignment titles