When I first read this term, I thought it was going to be about recipes, fractions, and standard math. Was I off. As I read it further I learned quite a lot about flour and measurements that I hadn't known before.
This math is based on the idea that the rest of the ingredients are expressed as a percentage of the total flour weight so the flour weight is counted as 100%. In other words if you have 500 grams of flour, your salt might be 2% or 10 grams of salt. If your water should be 80% then you would be using 400 grams of water.
I never thought of baking using this method. In addition, I read that you should not be using cups but you should have a scale to measure your flour by weight since a cup of flour can be between 115 and 150 grams. That is fairly large difference. The weight can also vary according to the type of flour you are using. Is it soft or hard wheat?
The other reason for wanting to use this formula rather than measuring by cups simply boils down to the fact that all cup measurements are not the same. Do you use a knife to level it? Do you shake it level? Do you use slightly rounded cups of flour? Since not all cups are created equal, using a formula means you have a better chance of having the end product turn out better.
Baker's math is also known as Baker's Percentage or Baker's Formula. This website explains it in detail for starting with a set amount of flour or starting with the size of the loaf you want and working backwards.
This is fortunate because I just got a scale I can try this idea with. The best scale is one you can zero out or tare with the container you are using to measure your flour or water or any other ingredient. I bought one that includes a bowl so next week I'll see how it goes.
Let me know if you use this method and how it works for you. I've recently acquired cookbooks that list the ingredients by weight rather than by standard measurement.