900dm+8000cm+400m=...m

900 dm - > m = 900 / 10 = 90 m

8000 cm - > m = 8000 / 100 = 80 m

= > 90 m + 80 m + 400 m

= 570 m

900dm =90m
8000cm=80m
400m=400m

90+80+400=570m

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