Homework: Piece of cake (for now)

Today I tackled my first homework assignment on probability. It surprisingly was really easy! It wasn't as hard as I thought it was going to be. Most of it was basic probability. For example, one problem stated, "A marble is selected at random from a jar containing 3 red marbles, 6 yellow marbles, and 4 green marbles. What is the probability that the marble is either red or green?" So to solve this you take the probability of getting a red marble (3/13) and add it to the probability of getting a green marble (4/13). The answer is 7/13! Most of the homework was as easy as this one. There were some harder problems, but I figured them out. The tricky part was learning how to decide if you add or multiply probabilities. When the question is asking for an "or" you should add and when it asks for an "and" you should multiply. Sometime you have to do both, but that is in the next homework section/chapter! More fun ahead!

I was searching the internet for ways to teach probability to my students and I came across this website full of worksheets I could give to my students to practice. It has answer sheets to all of the worksheets and it has different scenarios using probability, including using marbles and spinners! Click HERE to view!

Pick a card, any card!

Todays math lesson on probability was a little more challenging than last time. We used a deck of playing cards to practice probability. Some questions were easier like finding the probability of drawing a red card. Half of the deck is red so the probability of choosing a red  card was 26 over 52 which reduced to one half. 
Other questions were harder. One I had a hard time with asked to find the probability of drawing a red card or a 10. I solved it by finding the probability of each and adding them together. 
So I took the probability of getting a red, P(r)=26/52 and added it to the probability of getting a ten, P(10)=4/52 to get 30/52, but I forgot a step. 
My answer included the cards that were both red and 10. The question only asked for the chances of getting one or the other, not both. So you have to subtract the intersection: which is 2/52 because there are two cards that are both red and 10. So the real answer is 7/13 after you simplify. 
There were a couple questions that were similar to this question that confused me. I learned that when the question has 'or' in it, you need to subtract the intersection of both items. Also, I learned that to find the probability with an 'and' in the question you have to multiply the two item's probability to find the answer. For example; if you were to draw a card then return it to the deck and then draw again, what would be the probability that the first card is an ace and the second card is black? First, find the probability of drawing an ace: 4/52. Then find the probability of drawing a black card: 1/2. Now you add the two together and the the probability is 1/26!

This might sound a little confusing so here is an article about how to use a deck of cards for probability and examples to try. Click HERE to read it and try it out!

Probability Day 1

In math class yesterday, we started our first lesson on probability! instead of having a boring lecture on probability, we learned it through an activity. Normally, you would use goldfish for the activity, but we did not have any. Each group gets a baggy with a mixture of colorful goldfish. The green fish represent "sick fish" and any other color represents a "healthy fish." Then we had a worksheet that asked questions about the fish. My group had 37 "sick fish" and 11 "healthy fish." We had to find the probability that a fish in my sample would be healthy. Which would be the number of healthy fish I have over the total number of fish. (37/48) Some of the questions seemed tricky because I would over think them. For instance, one asked to add the probability of getting a "sick fish" plus the probability of getting a "healthy fish." So you would take 37 over 48 plus 11 over 48 and it would equal 48 over 48 or 1. Everyone would get the same answer to that question no matter how many fish they had. After we finished the fun activity we tried to complete the definitions on the back. It was amazing how much we understood because of the activity. I learned more from the activity than I would have in just a lecture. The best part about this activity is not only that it teaches probability, but you can give your kids a yummy snack when you finish it! ;)

This website also has many different fun games for children to play and to practice their probability skills. Click HERE to see!

First Post

Hello! This is my first blog so I give myself a pat on the back for figuring it out! This post is just to test it out, but don't worry, there is more to come!