17. Calculează:
a) 13 m + 548 cm = ... cm;

69 hm + 173 m = ... m;

59 km + 9 dam = ... dam;

b) 60 m – 468 cm = ... cm;

87 cm – 530 mm = ... mm;

15 km – 23 dam = ... dam;

c) 4500 m – 320 dam = ... dam;

7800 m – 49 hm = ... hm;

5500 m – 5 km = ... m.

(Scrie si transformarile numerelor, te rog!)