You need to check your spelling there, it can't be 'desa...', it will be either a decametre or a decimetre. Centi- (c-) = x 0.01 (one hundredth) Deci- (da-) = x 0.1 (one tenth) Deca- (d-) = x 10 (ten) Kilo- (k-) = x 1000 (thousand) So, 1 dam is equal to 10 m, and 1 dm is equal to 0.1 m, which is the same as 10 cm. From that, you can see that: 1 km = 100 dam 1 km = 10,000 dm