First, I want to apologize for not blogging this week. As you know, we've had parent teacher conferences each night and it's just been really busy! However, I definitely wanted to blog tonight to give examples on math in 7th and 8th grade. Unfortunately, my Mimio Pad is not working because it needs to be charged. The cord is at school! I have typed out the examples as best I can...I think it's still pretty clear, but please email me if you have questions!
Sixth Grade
The class was on a field trip today so I didn't have class with them. Your worksheets over fraction problems is due tomorrow.
Seventh Grade
Math - Sales Tax worksheet - Remember, you only have to do the front - #2-12. Find the tax AND the total. You will have two answers on each.
To find the tax, first you take the percent and change it to a decimal by moving the decimal point 2 places to the left. So if you have 7%, you would change that to .07 to make it a decimal. Once you have the decimal, multiply that by the dollar amount. Your answer is the tax. Be sure to round to the nearest cent (the second place after the decimal) if it doesn't look like money. So, if you have the following question:
Find the tax and the total on a new sweater that costs $49.75 with a tax rate of 6%. You would first change the 6% to a decimal by moving the decimal point two places to the left. (Remember, decimals are at the end of whole numbers.)
So 6% would become 0.06 and you would multiply that by $49.75. Once you multiply, you would have 2.9850 - the decimal goes between the two and the nine because there are 4 decimal places in the problem. But 2.9850 doesn't look like money.
You have to round to the 2nd decimal place. The 8 is the second place, so you look at the 5. Since it is a 5, it will make the 8 go up 1. So now you have 2.99 - you can drop off the 50. That now looks like money, so the tax is $2.99.
Remember, always think about if the answer makes sense. If you got the tax as 29.95 that wouldn't make sense because the item only cost $49.75! So to find the total, you would add $2.99 to $49.75 and get $52.74.
To solve one that has a fraction in it, you first need to change the fraction to a decimal and THEN change the % to a decimal. So, if you had 4 1/2%, you would first change that to 4.5%. Now you can move the decimal two places to the left to get 0.045 - that would be the decimal you would multiply by. Notice that there are three decimal places in this number now. PLEASE email me if you have questions!
Geography - For review over Chapter 6, complete the worksheets from each section. Many students finished in class or are almost done. Also, don't forget that if you haven't taken your country quizzes yet, you will have to do that tomorrow!
Eighth Grade
Pre-Algebra: To tell if a line is positive or negative that's on a graph, you would look at the line from left to right. If it is going up, it's a positive line. If it is going down, it is a negative line. To tell from an equation (which is what you will do for the top half), you look at the number that is in front of the x.
For example, if you are given these equations:
y = -2x +4 ; negative slope because there is a -2 in front of x.
y = 5x -3 ; positive slope because there is a +5 in front of x. (remember, a number is positive if there is no negative sign)
y = -1/2x -7 ; negative slope because there is a -1/2 in front of the x.
So that's pretty easy!
To graph the ones that are circled, you have to use the table of values like you did yesterday. So, make a table and put in the numbers -2, 0, 2 for the x values. This part is exactly like yesterday's assignment. Then, once you have the values for y, graph the line on a coordinate plane.
To do the bottom half of the assignment, you are checking to see if the ordered pair is a solution to the equation. If it isn't a solution, then that point wouldn't be on your line on the graph. You don't have to graph to find out though.
Here is an example:
y = -5x+9 (2, -1)
To tell, you would plug in the values for x and y from the ordered pair. An ordered pair is always (x, y) - so the first number is your x value and the second number is your y value. Put them in the equation and see if you get a true statement.
So: -1 = -5 times 2 + 9
-1 = -10 + 9
-1 = -1
Since this is true, (2, -1) IS a solution and you would write YES. You must show the work though. Don't just write yes or no.
Here is another example:
3x + 4y = -20 (3, -5)
You would plug in 3 for the x and -5 for the y like this:
3 times 3 + 4 times -5 = -20
9 + -20 = -20
-11 = -20
Since this isn't true, (3, -5) is NOT a solution and you would write NO.
Please email me if you are still confused! I'll be happy to help through email.
Algebra IFor each equation
today, you will find the slope and the y-intercept and then graph the line.
Remember, the slope is ALWAYS what is in front of the x. The y-intercept is ALWAYS the constant term after the x term. The line has to be written in slope intercept form, but you already know that the ones you are working with tonight are already written that way.
Here is an example of how to find slope and y-intercept:
y = -2/3x +5
Since -2/3 is in front of the x, -2/3 is your slope. You would write: m = -2/3
Since the constant term is 5, then your y-intercept is 5. You would write: b = 5
Now, to graph this, you would first put a point on the y-intercept and that means to put a point on the y-axis at that number. You would go up and put a dot at the 5.
Now, to do the slope, you look at it and see it is -2/3. That means the "rise" is -2. (If the slope is negative, the negative sign ALWAYS goes with the "rise".)
The run is 3 because it is on the bottom of the fraction. (If the slope is a whole number or NOT a fraction, the run will always be 1 because a 1 is always under a whole number.)
To graph the slope, you would put your pencil at the y-intercept, which is at the 5 on the y-axis in this problem, go DOWN 2 because your "rise" is -2, then go to the RIGHT 3 because your run is 3. Remember, you always RUN TO THE RIGHT. Now, put a dot at this point. You can do the slope again by going down 2 and going to the right 3 and putting another dot. Draw the line by connecting the dots.
Now, if your equation looked liked this:
y = x - 3, your slope would be 1, so you would write: m = 1
You know it is 1 because there isn't a number in front of the x, so it is understood to be 1!
If you had a problem like this:
y = -3x
your slope is -3, so you would write: m = -3
Since there is no number after the -3x, you have a y-intercept of 0! When you graph that, you would put a dot on the zero on the y-intercept, which is the origin and then go down 3 for the rise and to the right 1 for the run.
As always, email me if you have questions!
See you tomorrow,
Mrs. Swickey
