5u^2
just count the no. of squares
if they allocate sides or an area for the small square then:
sides
(side^2 • 5)
eg. the side is equal to 2cm, then
(2^2 • 5) = 4(5)
= 20 cm^2
allocated area for small square
square area • 5
eg. one square has an area of 4 cm^2
4 • 5 = 20 cm^2