4. Casting Nines

Similar to dividing by nine in that you are removing 9s from a number but this time we will not be dividing the male total by 9 we will be removing all the digits of 9 from a number.
19 we simply cross out the 9 to leave the female number 1.
949 cross out both 9s and we get a female number 4.

When a number contains digits that are not 9 we can remove any digit of 9 and add the remaining digits.
392 we can remove the 9 and then add the 3 to the 2 to get 5.

If the number is made up of only 9s then we must leave the last 9.
999 we can cross out two 9s and leave the last digit of 9.

So far so good.
We can also remove digits that have the sum of 9.
326 here 3+6=9 so we can remove the 3 and 6 to leave a 2. So the female number of 326 is 2.

It’s does not matter how we create 9 or how many digits we use to reach a total of 9 we can remove them.
1741 here we can add 1+7+1=9 so cross them out to leave the 4.

We can also remove multiples of 9.
8862 here we can add 8+8+2=18 so we can cross them out to leave the 6.

Imagine that 9 is a full pizza cut into nine slices.
8 has 1 slice missing
7 has 2 slices missing
6 has 3 slices missing
5 had 4 slices missing
So we can cast out more than just 9 but we will have to account for the missing slices.
85 Eighty five is made from the digits 8 and 5 if you imagine that the digits are two seperate pizza each with their respectives number of slices, we can make a complete pizza of 9 slices by giving a slice from the 5 to the 8.
This would make 4 and 9 we can cast out the 9 and leave the female number of 4. So when we cast out 8s we must reduce the value of one of the other digits by 1 similarly we can cast out 7s by reducing the value of any other digit by 2.

I hope you get the idea.
After a little practice you can find the female number of any male number in no time at all especially if you combine the other methods we have previously discussed.