This depends on your custom scoring system. You can use deimcals, or not.
For example: if the scoring rule is 1 point for every 10 yards passing, 57 yards yields 5.7 points with decimals and 5 points without decimals.
Your leagues specifically:
Winnipeg Fantasy Football League - Uses decimals
How Did These Get Up Here... - Does not use decimals
Le Magnifique - Uses decimals
You can view the scoring rules in detail for these leagues by expanding the "League Information" box and clicking the link under "Scoring".