c) 8g = 1/1000kg = 10/10000kg = 0,001kg
d) 1hg 25g = 0,125kg = 125/1000kg

2/
a) 0,5kg
b) 25/1000kg = 1/40kg = 0,025kg
c) 80/1000kg = 2/25kg = 0,08 kg
d) 125/1000kg = 1/8kg = 0,125kg
3/ 
a, 2 hm^2 34 dam^2 = 2 hm^2 + 0,34 hm^2 = 2,34 hm^2
b, 5 dam^2 67 m^2 = 5 dam^2 + 0,67 dam^2 = 5,67 dam^2
c, 12 dam^2 3 m^2 = 12 dam^2 + 0,03 dam^2 = 12,03 dam^2