Pre-Algebra Lesson Plans and Teaching Methods

Planning and Teaching Pre-Algebra

Pre-Algebra Topics

• Operations - add, subtract, multiply, divide, factor, round, the order of operations
• Properties - associative, commutative, distributive
• Equations
• Kinds of numbers - whole, integer, fractions, decimals and percents
• Exponents, powers and roots
• Monomials and polynomials
• Graphing
• Statistics, probability and estimating

Sample Lesson Plan for Finding Prime Factors

Lesson plans are specific to one topic and grade level. For this example, the topic is factoring numbers to 100 for fourth graders.

Objectives

Students will be able to define factor and prime number. They will be able to use a factor tree and the Sieve of Eratosthenes to find the factors of numbers up to 100.

Procedures

An attention-getting activity could be showing a YouTube.com video rap about factoring, prime numbers or both. If your classroom doesn't have access to the Internet, you can learn the rap and teach it to the class.

One of the most common ways to demonstrate a new concept is using visuals or manipulative objects. One manipulative that can be used with prime numbers and factoring is play money. Hold up a $5 bill and ask how you could divide it to share with class members. Demonstrate that you could either give the $5 bill to one student or give five students each a $1 bill.

Then show a $20 bill. Using the factor tree, show that you could give one student the $20 bill or two students a $10 bill. Continue breaking it down into the possibilities.

Finally, tell them that the $5 bill is a 'prime' bill because you could only divide it by itself or by one, but the $20 bill is not a 'prime' bill because you can divide it a number of ways. It is called a 'composite' number because it is 'composed' of more numbers than itself and one. Demonstrate using the factor tree on a few more numbers to discover whether they are prime numbers or composite numbers.

Teach the Sieve of Eratosthenes. Show the class a ten-by-ten chart of numbers to 100. Ask them to help you first to find the numbers that can be divided by two; explain that you leave the number two alone since it is a prime number. Cross out all the rest that can be divided by two because they are not prime numbers. Do the same with three, four, five and so on up through nine. The numbers that do not get crossed out are the prime numbers.

Review

A good discussion about prime and composite numbers can give students an opportunity to express what they've learned or are confused about. Ask how they think prime numbers are used in 'real life.' They might be interested in knowing that they are basic to most good codes, including those that are used every day for security on computer systems and cell phones.

Independent Practice

Homework, especially worksheets, may be used to give students practice. On the Internet, you can find a large number of worksheets for factoring. If students have access to computers at home, you might give them some URLs for interactive math games that emphasize factoring.