Why is 1 million milligrams 1 kilogram

Lets write it down

1000000 MG

now lets convert 1 million MGs to grams. every gram is 1000 miligram so we need to devide our original number by 1000 to convert it into grams

1000000:1000=1000

so 1 million MG is 1000 gram

now lets convert grams to kilograms.

a kilogram is 1000 grams so we need to devide 1000 grams by 1000 to convert it into kilograms

1000g:1000=1kg

there you go 1 million milligram is 1 kilogram.

so by what we learned from here. we can bypass this long procces and just devide by 1 million if we want to convert milligrams to kilograms (since 1 million milligrams is 1 kilogram)