Examine the picture and notice how the square is broken up into 25 square units. If you created a 100 square unit box and shaded in 40 of the squares, would that be the same as having four of the above shapes placed together to form a box?
What about a rectangle with 5 square units and 2 shaded squares? Can the shape above be rearranged to form 5 rectangles like the one pictured below?
Each of the farctions are equivalent to each other
because of the multiplicative identity as noted on
pg. 87 in your text.
Consider why using the identity changes the numbers of the fractions, but they are all still equivalent.