First thing you must do is read the word problem slowly and carfully, takeing note of all your numbers:
19 = all of the sunflowers
4 = how many flowers that can be put in each vase.
Now that w have all the number we can make the equation:
19 ÷ 4 = 4 3/4
Thus, there will be 4 vases with 4 sunflowers, and one vase with only 3 flowers.
Hope this helps! :)