How do I know when to use "El" or "La"?
You would use "El" with masculine nouns like "El Niño" and "La" with feminine nouns like "La Niña"
When doing an equation with different operations like multiplying, adding, and division, where do I begin?
You would need to start adding in that case but there is a way to remember the orders of operation and that is PEMDAS. Each letter represents an operation. P= Parenthesis E=Exponents M= Multiplication D=Division A=Addition S= Subtraction.
When subtracting when do I need to borrow?
When subtracting you would need to make sure that your top number is greater than your bottom number. If it is not you would have to borrow "1" from the next number at the top.