 Let's say I need to find a percent of problem, so especially dealing with budgets, so I make $2,400 a month in my income. $450 goes toward rent a month, so I want to figure out what percent of my budget goes toward rent. So the first thing I'm going to do is use a formula where I have part over base is equal to percent over 100. The part is going to be the piece that you pay, the base is going to be the total amount of your income, and then you always have 100 on the right hand side here because percent means out of 100. From my previous slide I know that I can substitute in the numbers for where they need to go in the place. $450 is the part that I pay, $2,400 is the total amount that I receive for income, so I have plugged in the numbers into my equation. To keep this simple I'm going to teach you a method that I use. So the first thing you're going to do is you're going to cross multiply the numbers that you have. For instance, the two numbers across from each other are $450 and $100. So I'm going to multiply $450 times $100. Remember whenever you multiply by $100, essentially what you're doing is adding $20 to the back of your number. So this becomes $45,000. So let's step one. Step two then is to take that amount and divide by what's left over, and what's left over is my $2,400. So I take $45,000, I divide by $2,400. Now the cool thing about division with zeros is that you can cancel off any zero on the back for zero together. So I can take off these two zeros and I can take off those two zeros. Once I cancel off my zeros this becomes a much easier problem to manage. Now it's $24,000 into $450,000. I can do those math problems. So I have to realize then how many times can $24,000 go into $45,000? Well I know that $2,000 times $2,000 is $4,000. That's going to get me pretty close but I think that's going to be too big so it's just going to go in once. I subtract and I end up with $21,000 left over. So now I bring down the remaining zero and I have to ask myself how many times can $24,000 go into $2,010? I'm going to guess it can go in off to the side. I'm going to try nine times and see if I get close or not. Nine times four is 36, nine times two is 18, nine times 21. Oh that's too big by six. So I've got to do my math off to the side and do 24 times eight. That leaves me with $192,000. So this eight goes up here because I'm multiplying eight times 24 to get $192,000. I subtract, I'm going to have to borrow. That leaves me with $18,000. Now I've used all my numbers but I can't leave a remainder so what I can do is put a decimal point and once I put a decimal point in I can buy as many zeros as I want. So I bring down my zero and now it's $24,000 into $180,000. So two goes into $18,000 nine times. I'm going to go $24,000 times $8,000 and do my math and see what I get. I've already done my work for the $24,000 times $8,000 and that's $192,000. That's too big. So I'm going to do my work and do 24 times seven which comes out with $168,000. So that's the one that I'm going to use up here. $168,000. I'm going to borrow and subtract. That leaves me with $12,000. Now I can continue this problem out but I don't really need to because the directions tell you to round the nearest whole number. So when I'm rounding and I have the number 18.7,000, if this is the whole number, this is the number that I look at for rounding. So because that is a five or higher, it bumps this eight up to a nine. So I spend 19% of my income on my rent.