Pt. a rezolva trebuie ca stii scara, adica: kg, hg, dag, g, dg, cg, mg
1) 3/4 kg+250 g= 0.75*1000+250=750+250=1000 g
3/4=0.75 kg
2) 1/2 dag+500 cg=500+500=1000 cg
1/2 dag= 0.5 dag= 0.5*1000=500 cg
3) 1t= 1000 kg
8/10t + 300 kg= 4/5t+300kg=0.8t+300kg=800kg+300kg=1100kg
regula de 3 simpla: 1t.....1000kg
0.8t.......x rezulta x= 800kg
4) 3/4g+120mg=0.75g+120mg=0.75*1000+120=750+120=870mg