Explanation & Answer:
You want to make sure both fractions have the same denominator.
10/12 and 1 4/6
We will convert the second fraction.
It is a mixed fraction, so we will make it an improper fraction.

Now we need to make it have the same denominator by multiplying.
2/2 * 10/6 = 20/12
The 10 day old worm is 10/12 inches long.
The 20 day old worm is 20/12 inches long.
This means the 20 day old worm is 10/12 inches longer. We can simplify this by dividing both the numerator and denominator by the same number - 2.
10/12 = 5/6
The 20 day old worm is 5/6 inches longer.