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20 mm  = 0.02 m = 2 x 10 ⁻²

0.005 mm = 0.000  005 m = 5 x 10 ⁻⁶

0.005 m = 5 x 10 ⁻³

0 . 000 000 2 mm  = 0. 000000 002 m =  0. 000 000 002 x 10 ⁻⁹

1/4 mm = 0.00 025 m = 2.5 x 10 ⁻⁴

18 cm = 0.18 m =  1.8 x 10 ⁻¹

70 cm = 0.7 cm = 7 x 10 ⁻¹

0.000 02  mm =  0.00 000 002 m = 2 x 10 ⁻⁸