Final answer:
To make the equation true, the missing number is 1/3.
Step-by-step explanation:
To find the missing number that would make the equation true, we need to determine the relationship between the given numbers. In this case, 2/3 is equivalent to 1/3 + 1/3, which shows that 1/3 added to itself equals 2/3. Therefore, the missing number would be 1/3.
Learn more about Finding missing numbers in equations