Thursday, October 29, 2009

Divisibility rules

Divisibility rules:

See text book pg. 135 for divisibility rules.

-Mr. Unkert

Greatest Common Factor

Greatest Common Factor (GCF) - the greatest common factor of two or more numbers is the largest factor they have in common.

To find the GCF of two numbers you can either use:
1. the listing method
2. the prime factorization method

The listing method:
list out the factors of each number and take the largest factor that they both share.

The prime factorization method:
Complete the prime factorization for each number. Multiply the pairs of prime factors that they both share together. Discard the prime factors that they do not both share. The product of the pairs of prime factors that they both share is the GCF.

equivalent fractions

Equivalent fractions: two fractions are said to be equivalent if they represent the same quantity.

To make fractions equivalent divide or multiply both the numerator (top number) and denominator (bottom number) of a fraction by a convenient number.

When dividing a convenient number is a number that goes both into the numerator and the denominator.

When multiplying a convenient number is a whole number greater than 1.

Prime factorization

Prime factorization - writing a composite number as a product of primes.

Prime number - a whole number greater than 1 that has exactly two factors.

Composite number - a whole number greater than 1 that has more than two factors.

To find the prime factorization of a number take than number and make a factor tree. Find the prime factors of that number using a factor tree. Write out the multiplication of those prime factors.

-Mr. Unkert

Friday, October 16, 2009

Notice periods B,F, and G

For those students who had difficulty on the last test a review session will be offered from 2:15 p.m. to 2:45 p.m. this coming Monday, Oct. 19th.

-Mr. Unkert

Sunday, October 4, 2009

Decimal Operations

Notes on:

Adding / subtracting decimals -
Line up the decimal point and add or subtract as normal

Multiplying decimals -
add the number of spaces the decimal point is from the right in each number being multiplied. Move the decimal point in the answer this amount from the right.

Ex. 1.1 x 1.1 = 1.21 (the answer's decimal point is two spots from the right)

Ex. 0.91 x 0.2 = 0.182 (the answer's decimal point is three spots from the right (2 +1))

Dividing decimals - make the divisor a whole number by moving the decimal point right. Move the decimal point the same amount right in the dividend. Divide as normal from this point.

Helpful reminder:
Add and Subtract keep it intact
Multiply and divide let it slide.

Thursday, October 1, 2009

Inverse operations

An operation that "undoes" another operation.

Ex. the inverse operation to adding 3 is to subtract 3, the inverse operation to dividing by 7 is to multiply by 7, etc.

Solving two step equations

The rules:
1. First undo the addition or subtraction using inverse operations
2. Balance the equation (whatever you do to one side of the equation do to the other)
3. Undo the multiplication or division of the variable using inverse operations
4. Balance the equation again.

Solving one step equations.

Rules for solving one step equations:
Whether the equation involves addition, subtraction, multiplication, or division the rules are the same:
1. Isolate the variable using inverse operations.
2. Balance the equation (what you have done to one side of the equation do to the other side)