Answer: he has 65/20 meters of string left
Explanation:
Montel bought a spool of string for making kites. It contained 10 3/20 meters of string. Let us first convert this length of string to improper fraction, it becomes 203/20 meters
He used 6 9/10 meters of string for kites. Changing 6 9/10 to improper fraction, it becomes 69/10 meters
To determine how many meters of string that Montel have left, we will subtract the length of string used from the total length of string. It becomes
203/20 - 69/10 = 203 - 138/20 = 65/20 meters of string left