Challenge yourself! – Grades 4-6 (Rectangle-squares)

In the following figure, area of the rectangle $ABCD$ is $24$ square units. Its length is a counting number of units, and so is its width. And, $ABEF, FEGH$ and $HGJK$ are three identical squares. What is the area of the big rectangle $ABJK$ ?

Note that counting numbers are $1,2,3,\cdots$ . So, length could be equal to, for example, $5$ units, but it could not be equal to $5.3$ units.