Answer:
0.25g + 0.05g + 500g = 500.30g
Step-by-step explanation:
The first step is converting everything to grams, by rules of three. Then we add.
In a rule of three problem, the first step is identifying the measures and how they are related, if their relationship is direct of inverse.
When the relationship between the measures is direct, as the value of one measure increases, the value of the other measure is going to increase too.
When the relationship between the measures is inverse, as the value of one measure increases, the value of the other measure will decrease.
Unit conversion problems, like this one, is an example of a direct relationship between measures.
First step: 0.5kg to g
Each kg has 1000g. So
1kg - 1000g
0.5kg - xg
x = 1000*0.5
x = 500g
0.5kg = 500g
Second step: 50mg to g
Each g has 1000mg. So:
1g - 1000mg
xg - 50mg
1000x = 50

x = 0.05g
50mg = 0.05g
Third step: 2.5dg to g
Each g has 10dg. So:
1g - 10dg
xg - 2.5dg
2.5x = 10

x = 0.25g
2.5 dg = 0.25g
Final step: Add
0.25g + 0.05g + 500g = 500.30g