Let's say our mystery number is n.
It would look something like this: 300 = 70% of n , but we need to change the format of the percentage.
70% = 70/100 = 0.7
Now our formula will look like this and we can solve it.
300 = 0.7n
---- -----
0.7 0.7
428.571428571=n
300 is 70% of 428.571428571.
