From the information given, Dairon already had a string that is 4 7/8 inches long.
We first write or simplify 3/8 and 4 7/8 in their decimal fraction forms.
3/8 is written as 0.375 and 4 7/8 is written as 4.875
We can now find out how many pieces he cut from the string (that was 4 7/8 inches), so:
4.875 ÷ 0.375 = 13
So he got 13 pieces of string. He wants 20 pieces, so;
20 -13 = 7
Therefore he will need 7 more strings .