Rounding:
If you are estimating you have to ask yourself some questions. For example if you had the number 218 you can either choose to round to the nearest one, ten, or hundred since it's a three digit number. Now let's say you are rounding to the nearest ten, you look at the digit beside the tens place value which is 8. Now you ask yourself is 8 higher than 5? Or lower than 5? Or you can ask yourself is 8 closer to ten? Or closer to 1? Of course 8 is closer to ten so now the number 218 turns into 220.
Estimating:
Estimating, when you are estimating maybe for an assignment or a test it's almost the same concept with rounding. For example, if you have a question asking you, estimate the total cost of the T.V and the sofa. T.V costs $499.99 and the sofa costs $239.99. Let's round the cost of the T.V to the nearest hundred, now you look at the next digit beside the hundreds place which is 9, so is 9 closer to 10? Or closer to 1? 9 is closer to 10, so now $499.99 tunrs into $500. Now when you are estimating the cost of the sofa which is 239.99, it is pretty much the same concept, you look at the digit beside the hundreds place, which is 3, so is 3 closer to 10? Or closer to 1? 3 is closer to 1. Now, 239.99 turns into $200. After you are done rounding the prices you add them together. 500+200= $700.00 and that is your estimated answer. If you calculate the real price 499.99+239.99= $739.98, so this estimate is close to the real answer.
Showing posts with label math. Show all posts
Showing posts with label math. Show all posts
Monday, 28 January 2013
Sunday, 27 January 2013
Converting Review ( percent,fractions,decimals)
How to convert Percent to Decimals:
Eg.
25% and 2.5% are examples of percent.
- so we need to find the decimal form of both of 25% & 2.5%
1. To do that, we first need to find the decimal point of the percent/number.
Remember: if you can't see thr decimal point of the percent/number, the decimal point is at the right end of the number.
Eg.
37% ( 37. <--- decimal point )
2. After we find the decimal point of the percent/number, we now move the decimal point 2x to the left then remove the percent sign.
Eg. #1
25.% -> 25. = 0.25 ( final answer )
^ <-- move the dec. p. to the left (2x)
Decimal point
Eg. # 2
2.5% -> 2.5 = 0.025
^ <-- move the dec. p. to the left (2x)
Decimal point
* always move the decimal point 2x to the left.
* if there's a gap/space when you move the decimal point like example number 2, just fill the gap with the number 0.
How to convert Decimals to Percent:
Eg.
0.25 and 2.5
- we need to convert 0.25 and 2.5 to percent.
1. First thing we need to do is to find the decimal point.
Eg.
0.25 2.5
^ ^
\ /
Decimal points
2. After that, we now move the decimal point 2x to the right then just add a percent sign (%).
Eg#1
0.25 ----> 0.25 + % = 25% ( final answer )
^ --->Move to the right (2x)
Decimal point
* if there's the number zero in front of the decimal numbers, just remove it.
Eg#2
2.5 ---> 2.5 = 250% ( final answer )
^ ---> move to the right (2x)
Decimal Point
* If there's a space when you move the decimal point just add zero to the space.
How to convert Percent to Fraction:
1. We turn the percent to decimal. ( You can see that in "How to turn Percent to Decimal".
Eg.
3.7 = 0.037
2. Now we need to identify the place value of the last number of decimal.
Eg.
0.037
0- tenths
3- hundredths
7- thousandths
Remember: The first number after the decimal point always starts with the place value of tenths.
3. After you 've identified the place value of the last number, we now make the decimal number a numerator and the denominator is based on the place value of the last decimal number.
Eg.
0.037 = 37/1000
^
Thousandths
* if there's a zero in front of the number, just remove it.
4. If the fraction can be simplified, simplify it. To do that, we must need to find a number that can divide both the numerator and the denomintor.
Eg.
25/100 divided both by 25 = 1/4
How to convert Fraction to Decimal:
1. We divide the numerator by the denominator.
Eg#1
5/8 = 5 divide by the number 8. --> 0.625
5- numerator
8- denominator
Eg#2
3 3/5 ( mixed fraction )
= 3 divide by the number 5
= 0.6 + 3
= 3.6
Remember: if you have a mixed fraction, just add the whole number to the answer of the numerator and denominator.
3 3/5
3- whole number
3- numerator
5- denominator
How to convert Decimal to Fraction:
1. We identify the place value of the last number of decimal.
Eg.
0.625
6- tenths
2- hundredths
5- Thousandths
2. We now place the decimal number(s) as the numerator of the fraction and the denominator is based by the place value of the last decimal number .
Eg.
0.625 --> 625/1000 = 5/8 ( final answer )
^
Thousandths Divide both numbers by 125
* if you can simplify the fraction, simplify.
Eg.
25% and 2.5% are examples of percent.
- so we need to find the decimal form of both of 25% & 2.5%
1. To do that, we first need to find the decimal point of the percent/number.
Remember: if you can't see thr decimal point of the percent/number, the decimal point is at the right end of the number.
Eg.
37% ( 37. <--- decimal point )
2. After we find the decimal point of the percent/number, we now move the decimal point 2x to the left then remove the percent sign.
Eg. #1
25.% -> 25. = 0.25 ( final answer )
^ <-- move the dec. p. to the left (2x)
Decimal point
Eg. # 2
2.5% -> 2.5 = 0.025
^ <-- move the dec. p. to the left (2x)
Decimal point
* always move the decimal point 2x to the left.
* if there's a gap/space when you move the decimal point like example number 2, just fill the gap with the number 0.
How to convert Decimals to Percent:
Eg.
0.25 and 2.5
- we need to convert 0.25 and 2.5 to percent.
1. First thing we need to do is to find the decimal point.
Eg.
0.25 2.5
^ ^
\ /
Decimal points
2. After that, we now move the decimal point 2x to the right then just add a percent sign (%).
Eg#1
0.25 ----> 0.25 + % = 25% ( final answer )
^ --->Move to the right (2x)
Decimal point
* if there's the number zero in front of the decimal numbers, just remove it.
Eg#2
2.5 ---> 2.5 = 250% ( final answer )
^ ---> move to the right (2x)
Decimal Point
* If there's a space when you move the decimal point just add zero to the space.
How to convert Percent to Fraction:
1. We turn the percent to decimal. ( You can see that in "How to turn Percent to Decimal".
Eg.
3.7 = 0.037
2. Now we need to identify the place value of the last number of decimal.
Eg.
0.037
0- tenths
3- hundredths
7- thousandths
Remember: The first number after the decimal point always starts with the place value of tenths.
3. After you 've identified the place value of the last number, we now make the decimal number a numerator and the denominator is based on the place value of the last decimal number.
Eg.
0.037 = 37/1000
^
Thousandths
* if there's a zero in front of the number, just remove it.
4. If the fraction can be simplified, simplify it. To do that, we must need to find a number that can divide both the numerator and the denomintor.
Eg.
25/100 divided both by 25 = 1/4
How to convert Fraction to Decimal:
1. We divide the numerator by the denominator.
Eg#1
5/8 = 5 divide by the number 8. --> 0.625
5- numerator
8- denominator
Eg#2
3 3/5 ( mixed fraction )
= 3 divide by the number 5
= 0.6 + 3
= 3.6
Remember: if you have a mixed fraction, just add the whole number to the answer of the numerator and denominator.
3 3/5
3- whole number
3- numerator
5- denominator
How to convert Decimal to Fraction:
1. We identify the place value of the last number of decimal.
Eg.
0.625
6- tenths
2- hundredths
5- Thousandths
2. We now place the decimal number(s) as the numerator of the fraction and the denominator is based by the place value of the last decimal number .
Eg.
0.625 --> 625/1000 = 5/8 ( final answer )
^
Thousandths Divide both numbers by 125
* if you can simplify the fraction, simplify.
Saturday, 26 January 2013
Pattering: Variables, expressions, equations, coefficients, etc.
For pattering, you'll be using a lot of variables. What are variables? Variables are letters that represents a number.
Eg.1 If you had an equation like this: 5+7 You would replace the number(s) with a letter. Instead of 5+7, you could have x+7. x=5 or you could also have 5+y. In this case, y=7. You could also have x+y, meaning your x equals 5 and your y equals 7. You could choose whatever letters you want to represent a number, it does not always have to be an x or a y.
Variables could be used to represent whatever topic or idea the x and y axis has.
For patterning, you'll also be using expressions. What are expressions? An expression is a number sentence without an equal sign.
Eg.1 Instead of having 3+9=12, you'll only need to add, 3+9.
Another important word you need to remember are equations. What are equations? Equations are used to help show a number sentence. A number sentence is basically a math question that uses any type of math devices, such as multiplication, addition, subtraction, or division. These devices are used to help calculate or get the answer of a math question(number sentence). You would also have to add an equal sign =. An equation is the same thing as an expression but you have to add an equal sign with the answer of the math equation.
Eg.1 7+8=15 would be an equation because it uses a math symbol that is needed to complete a math equation. It has the addition sign + an it also has the equal sign =.
For expressions, a multiplication sentence(without the equal sign) is shown a different way.
Eg.1 Instead of 4x3, you could either show it as 4(3) or 3(4), it doesn't really matter what order you put it in. You could also put it as a coefficient.
If you are working with variables, you will need to use something called a "coefficient". A coefficient is having a number go in front of a variable, this is used especially when you are multiplying, expressions, or equations.
Eg.1 6x3 is your expression. Let's say the 3 will be an x for our variable. We would have 6xx. This will get confusing because you don''t know if you're using a variable "x" or if you're using the multiplication sign. The rule to expressions or equations are to never show the multiplication sign unless you are using an x as a variable. It'll get confusing. This is when you use your coefficients. Instead of 6xx, you will only need to put 6x. (x=3) This shows that you are multiplying "x" 6 times. In this case, "x" is 3. You are multiplying 6 three times. Or you could do it the other way, 3x(x=6).
NOTE: Mrs. Boughton prefers you to put coefficients instead of putting it in brackets.
If we use graphs in class, make sure you label the graph chart. You need to label the x and y axis. The x axis is labelled going left and right(horizontally) and the y axis is labelled up and down(vertically). The x axis is usually labelled as the "Term #" for patterning. The y axis is usually labelled as whatever amount of shapes, toothpicks, or whatever type you are using for patterning.
There will be times when some of the worksheets will ask you for the value of the nth figure using words, numbers, and symbols. It just means to describe what you are doing.
Eg.1 There are three steps to completely answer the nth figure.
The equation using variables. 6x7=42. You'll need to have a variable for each number. In order to do that, you need to write down what number you want to change and write the number you want to replace the number with. If I wanted 6 to be a, I have to put "Let 6 be a." and if I wanted 7 to be h, I have to put "Let 7 be h" to let people know that this letter is the number you want it to be. You would also need to write down what is happening in your expression or equation. 6x7(Let 6 be n). 7n= 42 would be the equation you would need. You have to describe the equation. For example, "I am multiplying 7 by n(which is 6) and it all equals to 42.
To wrap up this up, make sure you figure out whatever pattern you need to answer.
Eg.1 If you had an equation like this: 5+7 You would replace the number(s) with a letter. Instead of 5+7, you could have x+7. x=5 or you could also have 5+y. In this case, y=7. You could also have x+y, meaning your x equals 5 and your y equals 7. You could choose whatever letters you want to represent a number, it does not always have to be an x or a y.
Variables could be used to represent whatever topic or idea the x and y axis has.
For patterning, you'll also be using expressions. What are expressions? An expression is a number sentence without an equal sign.
Eg.1 Instead of having 3+9=12, you'll only need to add, 3+9.
Another important word you need to remember are equations. What are equations? Equations are used to help show a number sentence. A number sentence is basically a math question that uses any type of math devices, such as multiplication, addition, subtraction, or division. These devices are used to help calculate or get the answer of a math question(number sentence). You would also have to add an equal sign =. An equation is the same thing as an expression but you have to add an equal sign with the answer of the math equation.
Eg.1 7+8=15 would be an equation because it uses a math symbol that is needed to complete a math equation. It has the addition sign + an it also has the equal sign =.
For expressions, a multiplication sentence(without the equal sign) is shown a different way.
Eg.1 Instead of 4x3, you could either show it as 4(3) or 3(4), it doesn't really matter what order you put it in. You could also put it as a coefficient.
If you are working with variables, you will need to use something called a "coefficient". A coefficient is having a number go in front of a variable, this is used especially when you are multiplying, expressions, or equations.
Eg.1 6x3 is your expression. Let's say the 3 will be an x for our variable. We would have 6xx. This will get confusing because you don''t know if you're using a variable "x" or if you're using the multiplication sign. The rule to expressions or equations are to never show the multiplication sign unless you are using an x as a variable. It'll get confusing. This is when you use your coefficients. Instead of 6xx, you will only need to put 6x. (x=3) This shows that you are multiplying "x" 6 times. In this case, "x" is 3. You are multiplying 6 three times. Or you could do it the other way, 3x(x=6).
NOTE: Mrs. Boughton prefers you to put coefficients instead of putting it in brackets.
If we use graphs in class, make sure you label the graph chart. You need to label the x and y axis. The x axis is labelled going left and right(horizontally) and the y axis is labelled up and down(vertically). The x axis is usually labelled as the "Term #" for patterning. The y axis is usually labelled as whatever amount of shapes, toothpicks, or whatever type you are using for patterning.
There will be times when some of the worksheets will ask you for the value of the nth figure using words, numbers, and symbols. It just means to describe what you are doing.
Eg.1 There are three steps to completely answer the nth figure.
The equation using variables. 6x7=42. You'll need to have a variable for each number. In order to do that, you need to write down what number you want to change and write the number you want to replace the number with. If I wanted 6 to be a, I have to put "Let 6 be a." and if I wanted 7 to be h, I have to put "Let 7 be h" to let people know that this letter is the number you want it to be. You would also need to write down what is happening in your expression or equation. 6x7(Let 6 be n). 7n= 42 would be the equation you would need. You have to describe the equation. For example, "I am multiplying 7 by n(which is 6) and it all equals to 42.
To wrap up this up, make sure you figure out whatever pattern you need to answer.
Friday, 25 January 2013
Mixed and Improper Fraction
Here are the steps to convert improper fractions to a mixed fraction:
E.g. 9/4
1) See how many times can 4 go into 9. 4 can go into 9 2 times.
2)4x2=8. 8 is still not enough so you check how many is left when you deduct 9 to 8.
3) It equals 1. 1 becomes your numerator and 2 becomes your whole number
4) Keep the same denominator which is 4
5) The answer is 2 and 1/4
Here are the steps to convert mixed fractions to improper fraction:
E.g. 5 and 3/4
1) Multiply the denominator to the whole number. 4x5=20
2) 20+ the numerator. 20+3=23
3) Keep the same denominator.
4) Your final answer is 23/4
E.g. 9/4
1) See how many times can 4 go into 9. 4 can go into 9 2 times.
2)4x2=8. 8 is still not enough so you check how many is left when you deduct 9 to 8.
3) It equals 1. 1 becomes your numerator and 2 becomes your whole number
4) Keep the same denominator which is 4
5) The answer is 2 and 1/4
Here are the steps to convert mixed fractions to improper fraction:
E.g. 5 and 3/4
1) Multiply the denominator to the whole number. 4x5=20
2) 20+ the numerator. 20+3=23
3) Keep the same denominator.
4) Your final answer is 23/4
Subscribe to:
Posts (Atom)