If one represents 1, then write the number represented by the diagram:
3402
Given that
One cube represents one.
Now, there are 3 cubes in thousands = 3000
There are 4 cubes in hundreds = 400
There are no cubes in tens.
There are two cubes in ones = 2
Hence, the number represented by the diagram = 3000 + 400 + 2 = 3402