What is the algebraic solution and expression for this question: A stray dog 812 of your muffins. That was 3/10 of all of them! With how many did you start

You would first put 3/10 as a decimal: 0.3

Then you know there's a remaining 7/10 somewhere

You then put that as a decimal: 0.7

After that, you multiply 812 by 0.7 which would give you the 7/10 missing

Add those together and you get your answer: 1380.4 muffins