Ordinal level of measurement: When the possible observations are tags or categories or names, with a natural ordering, the level of measurement is ordinal, arithmetic operations cannot be performed even if the values are numerical.
Interval level of measurement: When the possible observations are numerical values that can be added or subtracted, but not divided or multiplied, the level of measurement is interval, zero is not absolute, but relative.
In both ordinal and interval data, there is natural order of the data. The sequence in which the values of the variable occur is meaningful in both cases.
The mode and median exist for both of the scales. This is because, the mode is the most frequently occurring in a data set, which can be obtained for both ordinal and interval scale variable, again, the median is the value that lies in the middle most position of an ordered arrangement of all value in the data set, which can also be obtained for both the scales.
Moreover, the division and multiplication operations cannot be done for both of the variables.