Windy's Algebra Post

Algebra - Writing mathematical phrases using letters to represent numbers:

eg. n+9=16

n=7

Variable - The unknown -use a letter to represent a number

eg. a+12=14

Constant - The integer in an algebraic expression or equation

Equation - 2x = 6

Expression - 2x -

Solving an Algebraic Equation:

1) Isolate the variable

2) Cancel the constant using zero pair

3) Balance, doing it to both sides

4) Verify your answer

Two-Step Equations

(Subtraction/Multiplication)

(Addition)

One-Step Equations

(Divide)

Windy's Cylinder Volume and Volume Problems

Chapter 7.3










a) V= π.r.r.h
V= (3.14.5.5).23
V= 78.5
V= 1805.5 cm3

Chapter 7.4













a) Yes, he has enough small prism.

b) ( 22.47 m3
v= (b x h1/2) x h2
v= (1.4 x 1.7/2) x 1.18
v= 1.19.1.18
v= 1.4042 m3
1.4042 x 16= 22.4672.7 -> 22.47 m3

1.4042 x 4 = 5.6168 -> 5.6 m
1.4042 x 4 = 6.88058 - > 6.8 m

Windy's Great Big Book of Integers

Chapter 1 Grade 7 Integer Review

(+4) + (-2) = +2

Positive (4) and Negative (2) = positive 2

have 4 and owe 2 = have 2

Standard Form:

4 - 2 = -2

Make zero pairs:

-16 = +16, -5 = + 5, +6 = -6, -2 = +2, -10 = +10,+3 = -3,+1

1 = -11, -9 = +9

Chapter 2

Multiplying Integers

(-2) x (+3)

(+3) x (-2) = -6

remove 2 groups of (+3) --> use zero pairs remove and...

(+2) x (+3) = +6

2 groups of (+3) = +6

(-2) x (-3) = +6

remove 2 groups of (-3) = +6

(2) x (+3) = -6

2 groups of (-3) = -6

Sign Rule (negative signs)

Even - When you have an even number of NEGATIVE factors the product is POSITIVE.
ODD - When you have an odd number of NEGATIVE factors the product

is NEGATIVE.

Chapter 3 Division Integers

Partitive Division:

Quotative Division:

Sign Rule for Division:

Chapter 4: Order of Operations with Integers

How I would solve this problem is first follow BEDMAS I would first put brackets on (-6) ÷ (-3) so it would look like this [(6) ÷ (-3)] and you would get an answer of -2 then I solved (+5) x (-3) = -15 So then I added -15 + -2 = -17

Windy's Final Percent Post

A Percent means out of 100. It is another name for hundredths.

eg. 65% = 65 out of 100, 65/100 or 0.65 = 65%

4.1 Representing Percents - Means showing a percent as a picture in a hundred grids.

eg. 55% on a hundred grid 55 squares would be shaded, so it is 55%

4.2 Fractions, Decimals and Percents - A percent that includes a portion of a percent.
eg. 7 3/8 or 4.5%
Percents can be written as fractions and decimals.
eg. 1/2% = 0.5, 0.5/100 = 0.005
Percents can also be combined by adding to solve problems.
eg. 5%+7%=12%

4.3 Percent of a Number - Mental math strategies such as halving, doubling, and dividing by ten to find the percent of some numbers. To calculate the percent of a number, write the percent as a decimal then multiply by the number.

eg. 12 1/2= 12.5% = 0.125 12 1/2% of 50 = 0.125x50= 6.25

4.4 Combining Percents

* percents can be combined by adding to solve problems.

* to calculate the increase in a number.

* you can add the combined percent amount to the original percent.

* you can multiply the original number by a single percent greater than 100.

* percents of percents can be used to determine amounts that result from consecutive increases or decreases.

Link: http://mathforum.org/dr.math/faq/faq.fractions.html

Video: http://www.youtube.com/watch?v=X1gAxh3ztoo&feature=channel

Understanding Percents
Percent Review Video