What is the percent of change from 100,000 to 10,000?

-- To change from 100,000 to 10,000 the quantity is reduced by 90,000.

-- 90,000 (the reduction) is 90% of the original 100,000 .

-- So the original quantity is reduced by 90% .

So assuming 100000 is 100% then treat as fraction
change=100000-10000=90000
so the change=90000/100000
90000/100000 simplfies to 9/10

percent means parts out of 100 so
9/10 times 10/10=90/100=90%
so percnet change=90%