2x is subtracted from the square of a number

In a box lenght 1m breadth 60 cm and height 40 cm small rectangular packets of dimension 5 cm into 8 cm into 10 cm are packed. how many such small packets can be packed in the big box?

Answer question above and explain each step : )

Look at this pattern ; 1,4,9, number 10000 belongs in this pattern . what’s the place of this number?