What is a complement in maths?

Eg what would you put for the question: What is the complement of $16$ to $20$ ? Thank you so much for the help if you do!

Jul 11, 2018

$1 - 5 , 6 - 10 , 11 - 15 , 16 - 20. . .$

Explanation:

The complement of $16 \to 20$

Now the difference between the range is $4$

A complement is a unique value that can be used to complement another value if not used, they have similarities..

Hence a similar or complement range is $1 - 5 , 6 - 10 , 11 - 15. . .$ and so on..