2 x 4 8. Then 540-5355 350-3464 ie 549. This will help you work out the math faster since you know the exact steps in using the formula.
When you need to learn formulas also learn the conditions for each formula it might be something like if x 0.
Loan to Value LTV Ratio. Its not just addition when it comes to maths its like everything that is related to mathematical is troubling. Also draw a relevant diagram or graph each time you write the formula it might be a parabola or perhaps a circle. Use different channels to learn the formula.