1km² =100公顷 =1000000m²(6个0) =100000000dm²(8) =10000000000cm²(10)
1公顷=10000m² =1000000dm²(6) =100000000cm²(8) =0.01km²
1m² =100dm² =10000cm² (4) =0.0001公顷(小数点后3个0) =0.000001km²(5)
1dm² =100cm² =0.01m²(1) =0.000001公顷(5) =0.00000001km²(7)
1cm² =0.01dm² =0.0001m²(3) =0.00000001公顷(7) =0.0000000001m²(9)