Cracking the Math Section of the T-COM

Basic Math | Geometry | Algebra | Strategies | Practice

For help with the math section,complete the following review sheets (MATD 0370, MATD 0390, and MATH 1314) at: http://www.austincc.edu/math/prereqreviews.html. Then follow up with any math tutor in one of the Learning Labs.

Obtain a blue Assessment Referral form from the Assessments Center (CYP 2116) before coming to the Learning Lab. Contact Assessment at Cypress at 512.223.2020.

The Mathematics Test assesses students’ knowledge in three levels of math skills: pre-algebra/numerical skills, algebra, and college algebra and results in placement into the appropriate skill building mathematical course or approval for enrollment into a college-level mathematical course. Pre-algebra/numerical skills items range from basic math concepts and skills (integers, fractions, and decimals) to the knowledge and skills that are required in an entry-level algebra course (absolute values, percentages, and exponents). The algebra items are essentially questions from elementary and intermediate algebra (equations, polynomials, formula manipulations, and algebraic expressions). The college algebra test items measure algebra knowledge and skill in operations with matrices, functions, and factorials.

You will be permitted a calculator, scratch paper, and pencil.

You will not be allowed to return to previous questions in order to change your answers. You must answer each question presented to you. You will not be penalized for guessing.

Multiple-choice items in each of the five mathematics placement areas test the following:

  • basic skills—performing a sequence of basic operations
  • application—applying sequences of basic operations to novel settings or in complex ways
  • analysis—demonstrating conceptual understanding of principles and relationships in mathematical operations

Students are permitted to use approved calculators when completing the COMPASS® mathematics placement or diagnostic tests.

Click here to see the interface for the Compass Math Test.

Click here for ACC Math Prerequisite Review sheets.

 Scoring

Your test scores determine which course you are to be placed in at Austin Community College:

  • 0-25 places you in Basic Math Skills
  • 26-38 places you in Topics of Developmental Math or Elementary Algebra
  • 39-45 places you in Elementary Algebra
  • 46-68 places you in Intermediate Algebra
  • 69-79 places you in College Algebra, Topics in Math, Statistics, or Math for Business and Economics (see an advisor)
  • 80-100 places you in higher level courses like Trigonometry (see an advisor)
Click here for more information on interpreting your score.

Basic Math

Click here for Basic Math Review.

Click here for Basic Math Tutorial.

EXPONENTS and ROOTS

Click here for lectures on EXPONENTS & ROOTS.

Rule 1: Am = A x A x A

Rule 2: A-m = 1/ Am

Rule 3: Am + An = A m + A n

Rule 4: Am x A n= Am+n

Rule 5: (Am )n = Amn

Rule 6: Am /An = Am-n

Rule 7: Any quantity except zero, raised to the zero power is 1." That is, zero to the zero power doesn't equal one; it equals zero.

SCIENTIFIC NOTATION

This shouldn't be a problem for you since you can use your calculator.

For example: 4 x 105 = 400,000; 7 x 104 = 70,000. Just count the number of zeros to the right of the number.

(4 x 106 )(7 x 107 ) = (4 x 7)(1013 ) = 28 x 1013 = 2.8 x 1014

Positive & Negative Numbers

  • A number greater than 0 is positive.
  • On the number line, positive numbers are to the right of 0.
  • A number less than 0 is negative.
  • On the number line, negative numbers are to the left of 0. Zero is the only number that is neither positive nor negative; it divides the two sets of numbers.
  • On the number line, numbers increase to the right and decrease to the left.
  • The expression x > y means that x is greater than y. In other words, x is to the right of y on the number line.

Miscellaneous Properties of Positive and Negative Numbers

1. The product (or quotient) of positive numbers is positive.
2. The product (or quotient) of a positive number and a negative number is negative.
3. The product (or quotient) of an even number of negative numbers is positive.
4. The product (or quotient) of an odd number of negative numbers is negative.
5. The sum of negative numbers is negative.

ABSOLUTE VALUES

When you have an absolute value, perform the operation within the brackets just like it was a parenthesis before you apply that absolute value.

For example: |7 + 6 - 18| = | - 5| = 5.

The absolute value of a number is its distance on the number line from 0. Since distance is a positive number, absolute value of a number is positive.

If the number is negative, simply make it positive; and if it is already positive, leave it as is. For example, since -2.4 is negative, | -2.4 | = 2.4 and since 5.01 is positive,

| 5.01 | = 5.01.

If the variable is positive, simply drop the absolute value symbol. For example, If x > 0, then | x | = x. If x < 0, then | x | = -(x).

PROBABILITY

Probability is the number of desired or looked for outcomes divided by the number of possible outcomes. Two examples follow:

You have 8 blue shirts, 6 red shirts, and 4 white shirts. After you take a blue shirt out, what's the probability you will take a blue shirt out again?

The key here is to remember to subtract from your total. In this case, we have 7 blue shirts left and a total of 17 shirts in the closet. So you have a 7 in 17 chance of pulling out a blue shirt.

You have two dice, each numbered from 1 - 6. What is the probability that you will roll a combination that totals 2?

When you look at this analytically, you realize that you have only one combination that will result in a 2. Both dice need to turn up with 1's. How many total combinations are possible? If you roll a 1 on one cube, how many other possible numbers can come up on the other cube? Six! So, you have six combinations of six each --or 36 total combinations. So the answer is 1/36.

Click here for more on Probability.

GEOMETRY

Click here for Plane Geometry Review.

Click here for an extensive Formula Guide.

Click here for lectures on COORDINATE GEOMETRY.

Learn the basic rules below:

1. There are 180 degrees in a straight angle.

2. Two angles are supplementary if their angle sum is 180 degrees.

3. Two angles are complementary if their angle sum is 90 degrees.

4. Perpendicular lines meet at right angles.

5. A triangle with two equal sides is called isosceles. The angles opposite the equal sides are called the base angles.

6. The angle sum of a triangle is 180 degrees.

7. In an equilateral triangle all three sides are equal, and each angle is 60 degrees.

8. The area of a triangle is bh/2, where b is the base and h is the height.

9. In a triangle, the longer side is opposite the larger angle, and vice versa.

10. Pythagorean Theorem: In a right triangle, the square of the two sides that form a right angle is equal to the square of the longest side.

11. Two triangles are similar (same shape and usually different size) if their corresponding angles are equal. If two triangles are similar, their corresponding sides are proportional.

12. Two triangles are congruent (identical) if they have the same size and shape.

13. In a triangle, an exterior angle is equal to the sum of its remote interior angles and is therefore greater than either of them.

14. Opposite sides of a parallelogram are both parallel and congruent. Area of a parallelogram: A = bh (b = base and h = height)

15. The diagonals of a parallelogram bisect each other.

16. If w is the width and l is the length of a rectangle, then its area is A = lw and its perimeter is P = 2w + 2l.

17. The volume of a rectangular solid (a box) is the product of the length, width, and height. The surface area is the sum of the area of the six faces. V = bhw (b = base, h = height, w = width)

18. If the length, width, and height of a rectangular solid (a box) are the same, it is a cube. Its volume is the cube of one of its sides, and its surface area is the sum of the areas of the six faces.

19. An angle inscribed in a semicircle is a right angle.

21. Area of a circle: A = pi times the radius squared. (Note: Pi = approximately 3.14. Pi is an infinite, non-repeating decimal.)

22. Circumference of a Circle: C = pi x d (pi = 3.14 and d = diameter)

23. Volume of a Cylinder: V = pi times the radius squared times the height

Slope Formula:

The slope of a line measures the inclination of the line. By definition, it is the ratio of the vertical change to the horizontal change. The vertical change is called the rise, and the horizontal change is called the run. Thus, the slope is the rise over the run.

Given the two points (x, y) and (a, b) the slope(M) is:

M = (y - b)/(x - a)

The y-coordinate of the point where a line crosses the y-axis is called the y-intercept.

Slope-Intercept Form of a Linear Equation

y = mx + b, where m = slope and b = y-intercept.

Click here for more on Slope-Intercept Form.

The length of the line segment, d, is "the square root of the sum of the squares of the other two sides":

d = [(x2 - x1)2 + (y2 - y1) 2] 1/2

Click here to review the Distance Formula.

Midpoint Formula

The midpoint M between points (x, y) and (a, b) is given by:

M = ([x + a]/2, [y + b]/2)

In other words, to find the midpoint, simply average the corresponding coordinates of the two points.

Click here to review the Midpoint Formula.

Algebra

Click here for Algebra Modules from Brazosport ISD.

Click here for tips on Solving Simple Equations.

Click here for Algebra Tutorial.

Click here for Algebra I Review.

Click here for lecture on the Quadratic Formula.

Click here for lecture on Polynomials.

Adding & Subtracting Algebraic Expressions

1. Only like terms may be added or subtracted. To add or subtract like terms, merely add or subtract their coefficients:

2. You may add or multiply algebraic expressions in any order. This is called the commutative property:

x + y = y + x

xy = yx

Caution: the commutative property does not apply to division or subtraction.

3. When adding or multiplying algebraic expressions, you may regroup the terms. This is called the associative property:

x + (y + z) = (x + y) + z

x(yz) = (xy)z

Caution: the associative property doesn't apply to division or subtraction.

4. Parentheses

When simplifying expressions with nested parentheses, work from the inner most parentheses out:

5x + (y - (2x - 3x)) = 5x + (y - (-x)) = 5x + (y + x) = 6x + y

5. Order of Operations: (PEMDAS)

When simplifying algebraic expressions, perform operations within parentheses first and then exponents and then multiplication and then division and then addition and then subtraction. This can be remembered by the mnemonic:

PEMDAS

Please Excuse My Dear Aunt Sally

(parentheses, exponents, multiplication, division, addition, subtraction)

INEQUALITIES

Inequalities are manipulated algebraically the same way as equations with one exception:

Multiplying or dividing both sides of an inequality by a negative number reverses the inequality. That is, if x > y and c < 0, then cx < cy.

Example: For which values of x is 4x + 3 > 6x - 8?

As with equations, our goal is to isolate x on one side:

Subtracting 6x from both sides yields -2x + 3 > -8
Subtracting 3 from both sides yields -2x > -11
Dividing both sides by -2 and reversing the inequality yields x < 11

Click here for lecture on solving Word Problems.

Strategies

SUBSTITUTION

Substitution is a very useful technique for solving math problems. It often reduces hard problems to routine ones. In the substitution method, we choose numbers that have the properties given in the problem and plug them into the answer-choices.

When using the substitution method, be sure to check every answer-choice because the number you choose may work for more than one answer-choice. If this does occur, then choose another number and plug it in, and so on, until you have eliminated all but the answer. This may sound like a lot of computing, but the calculations can usually be done in a few seconds.

When substituting in quantitative comparison problems, don't rely on only positive whole numbers. You must also check negative numbers, fractions, 0, and 1 because they often give results different from those of positive whole numbers. Plug in the numbers 0, 1, 2, -2, and 1/2, in that order.

Plugging In

Sometimes instead of making up numbers to substitute into the problem, we can use the actual answer-choices. This is called Plugging In. It is a very effective technique, but not as common as Substitution.

NUMBER THEORY

At first, students often struggle with these problems since they have forgotten many of the basic properties of arithmetic. So before we begin solving these problems, let's review some of these basic properties.

A number n is odd if the remainder is one when n is divided by 2: n = 2z + 1.

Consecutive integers are written as x, x + 1, x + 2, . . .

Consecutive even or odd integers are written as , x + 2, x + 4, . . .

The integer zero is neither positive nor negative, but it is even: 0 = 2(0).

A prime number is an integer that is divisible only by itself and 1.

The prime numbers are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, . . .

A number is divisible by 3 if the sum of its digits is divisible by 3. For example, 135 is divisible by 3 because the sum of its digits (1 + 3 + 5 = 9) is divisible by 3.

RATIO AND PROPORTIONS

1. A recipe for 60 cookies uses 3 cups of flour. How many cups of flour will be needed to make 150 cookies?

When you can, set proportion problems up as ratio as in this case: 60/3 = 150/X. By setting this problem up as a ratio, you can solve it by cross multiplying and it allows you to be able to check to make certain your ratio is set up to compare like entities.

2. A high school has 700 students. The ratio of freshmen to sophomores to juniors to seniors is 4:3:2:1. How many juniors are there?

The high school has 700 students. They are in a ratio of freshmen to sophomores to juniors to seniors of 4 to 3 to 2 to 1.

4X + 3X + 2X + 1X = 700

10x = 700

x = 70

2x = 2(70) = 140 juniors

In many word problems, as one quantity increases (decreases), another quantity also increases (decreases). This type of problem can be solved by setting up a direct proportion.

Example: If Biff can shape 3 surfboards in 50 minutes, how many surfboards can he shape in 5 hours?

(A) 16 (B) 17 (C) 18 (D) 19 (E) 20

As time increases so does the number of shaped surfboards. Hence, we set up a direct proportion. First, convert 5 hours into minutes: 5 hours = 5 x 60 minutes = 300 minutes. Next, let x be the number of surfboards shaped in 5 hours. Finally, forming the proportion yield

3/50 = x/300
3(300)/50 = x
18 = x

The answer is (C).

Example: If 7 workers can assemble a car in 8 hours, how long would it take 12 workers to assemble the same car?

(A) 3 hrs. (B) 3 1/2 hrs. (C) 4 2/3 hrs. (D) 5 hrs. (E) 6 1/3 hrs.

As the number of workers increases, the amount time required to assemble the car decreases. Hence, we set the products of the terms equal. Let x be the time it takes the 12 workers to assemble the car. Forming the equation yields

7(8) = 12x
56/12 = x
4 2/3 = x

The answer is (C).

To summarize: if one quantity increases (decreases) as another quantity also increases (decreases), set ratios equal. If one quantity increases (decreases) as another quantity decreases (increases), set products equal.

Factoring using the Distributive Rule

The most basic type of factoring involves the distributive rule:

ax + ay = a(x + y)

For example, 3h + 3k = 3(h + k), and 5xy + 45x = 5xy + 9(5x) = 5x(y + 9). The distributive rule can be generalized to any number of terms. For three terms, it looks like ax + ay + az = a(x + y + z). For example, 2x + 4y + 8 = 2x + 2(2y) + 2(4) = 2(x + 2y + 4).

Example: If x - y = 9, then (x - y/3) - (y - x/3) =

(A) -4 (B) -3 (C) 0 (D) 12 (E) 27

(x - y/3) - (y - x/3) =
x - y/3 - y + x/3 =
4x/3 - 4y/3 =
4(x - y)/3 =
4(9)/3 =
12

The answer is (D).

FOIL METHOD

First - Multiply the first term in each parenthesis.

Outer - Multiply the outer term in each parenthesis.

Inner - Multiply the inner term in each parenthesis.

Last - Multiply the last term in each parenthesis.

Click here for more about the FOIL method

PRACTICE

West Texas A&M THEA Review

Purple Math

Math for Morons

Math Contest

Math Planet

Compass Prep Syllabus |  The Reading Section | The Writing Section | Blackboard

 

 Created by Becky Villarreal Austin Community College 2000