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Studying for a test? Prepare with these 15 lessons on Equations, expressions, and inequalities .
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- Let's do a few examples of writing expressions to help us solve word problems. So they tell us Susie ran a race. She ran five miles an hour, and the race took her t hours to complete. How long was the race? Write your answer as an expression. Alright, if we're trying to figure out the number of miles, you'd want to take her speed, which is in miles per hour, so five miles per hour times the number of hours. So the number of hours is t, so you can literally just write that as five t. Five t literally means five times t. Now another way you could have done it is you could have used this little dot symbol here. This is not a decimal, it sits higher than a decimal, and it means multiplication, five times t, either of these, five dot t or five t means five times t, it makes sense. You take your speed times your time, and you'll figure out how far you actually went. Let me check my answer here. Let's do a few more of these. The Running Aces card team won $548 playing poker in tournaments last year. The winnings were split evenly among the p players. How much of money did each, I guess you'd say how much money, not how much of money, it's a grammatical error. How much money did each player receive? Write your answer as an expression. So they had $548, and they had to split it evenly among the p players, so they're gonna split it, so I'm just gonna go backslash here, or I literally could have just clicked on this as well, 548 divided by p. I'm gonna divide the amount of money we got amongst the number of players. So that's how much money each player actually receives. Let's check the answer, we've got it right. Let's do a few more of these. Phil received a prize of x dollars from a poker tournament. The tournament cost him $100 to enter. What were Phil's net winnings from the tournament? Write your answer as an expression. Alright, his net winnings, okay. He gets x dollars, but it's not like he just walks away with x, I means, he does get the x dollars, but he had to pay something to enter the tournament. He had to pay $100 to enter the tournament, so for example, if x was $105, he wins $105, but if he had to spend $100 to enter the tournament, then his net would be 105 minus 100, or five dollars, so this is giving us the net. We're getting how much he got, but we're subtracting how much he actually had to spend. Let's do one more of these. Hillary made 48 chocolate chip cookies and y sugar cookies. How many total cookies did Hillary make? Well, 48 chocolate chip cookies, and then you add that, the number of sugar cookies she made, and there you have it. That's the total number of cookies she made. If she made two sugar cookies, y would be two, and she would've made a total of 50 cookies. If she made 100 sugar cookies, then this would be 100 plus 48 which would be 148 total cookies. So hopefully that gives you a little bit of practice, and I encourage you to do this exercise so you get a lot more practice.