Final answer:
Each friend will receive 4 antique letters.
Step-by-step explanation:
In order to find out how many antique letters each friend will receive, we need to divide the total number of letters by the number of friends. If Sacha has a box of antique letters and wants to give an equal number to each of her 5 friends, she would divide the total number of letters by 5. Let's say Sacha has 20 antique letters in total. When she divides this by 5, each friend will receive 4 antique letters.