How many milligrams make one kilogram?

Hint- 1 kilogram (kg) = 1000 gram (g) & 1 g = 1000 mg.

As we know that 1 kilogram (kg) = 1000 gram (g)………… (1)
And we also know that 1 gram = 1000 milligram……….. (2)
So, from equation (1) and (2) we have
1 kilogram (kg) = 1000 gram (g)
$ \Rightarrow 1kg = 1000 \times 1000$ milligram
$ \Rightarrow 1kg = {10^6}$ milligram.
Hence ${10^6}$ milligram makes 1 kilogram.

Note- In such types of questions the key concept we have to remember is that always remember the unit conversion i.e. from kilogram to gram and gram to milligram, then we easily solve these types of questions using the unit conversion method as above.