FORMULATING EQUATIONS

Annah Kuriakose

7th Grade Math

3rd Period

June 23, 2009

Approximate Time:

50 minutes

OBJECTIVE:

TSW will learn how to formulate algebraic equations to reflect a given situation. (DOK 2, 2c)

MATERIALS:

paper, pencil, dry erase markers, guided notes, butcher paper, markers, tape

WARM UP: (4 min)

Write an algebraic EXPRESSION for the following:

Five more than a number [is 25]

Seventeen divided by a number [is 500]

Three times a number [is 14]

A number decreased by twenty [is 72]

SET: (3 min)

Has anybody ever been to a park? Do you guys know what a see-saw is? How does a see-saw work? Two people sit on either end and push off the ground so they go up and down, right? Now, when is a see-saw the most fun? When one person’s much heavier than the other or when they’re the same weight? Right, when they’re the same. Today we’re going to learn about mathematical expressions that are equal to each other. That means they have the same VALUE. So if we think about our see-saw analogy, that means our mathematical see-saw would be balanced. So far we’ve been talking about forming expressions. Now we’re going to give those expressions values by adding an equals sign. We learned yesterday that an equals sign means that the expression becomes an equation. Today we’re going to be writing equations.

PROCEDURES:

A. Brainstorming/learning vocab (10+2 min= 12 min).

Draw a five-columned table on the board and ask students to copy it into their books. Have them turn their attention to the board once they’ve copied the table. Choose a student volunteer to be the scribe and from the back of classroom, ask students what words they associate with addition, subtraction, multiplication, division, and equals. Write down what they say in their own words. When list is complete, give students one or two minutes to copy down graph into notebooks.

[Should look something like:

AdditionSubtractionMultiplicationDivisionEquals

Increased bydecreased bytimes (as many)divided byis [spend some time on this]

Greater thanless thanmultiplied bydivided intothe same as

More thantaken fromequivalent to

Added tosubtracted from]

B. Modeling/Think-Aloud (3 minutes)

Now, using my lists of words, I’m going to turn a group of words into what we call an algebraic equation. I just want you to watch me. Keep your eyes on me and your pencils down.

Ex. Fifteen more than a number is 18

So I’m thinking, I know that ‘more’ means addition [use colored marker to indicate this] and that ‘a number’ means an unknown number for which I’m going to use a variable, like x [use another color]. I also know the importance of the word ‘is’ which means equals [use another color]. So let’s see, 15 + x = 18. And there’s my algebraic expression. I want everyone to copy down the sentence into their notebooks, and copy down the notes that I made on it. I know you don’t have colors, but you’ll get to use them in a activity we’ll do in a little bit.

C. Guided Practice. (8 min)

Use bell ringer examples WITH added parenthetical citations. Use cold calling to walk through each expression, identifying parts of the phrase that will help to write the equation. Have them copy down what I do into their notes.

D. Independent work (12 min)

Complete this worksheet. I’m going to walk around; raise your hand if you have any questions. I’d like you to mark the words just like we did in the practice examples. From there, write the equations in the space given. When you’re done, choose one for poster, and write in LARGELY on the construction paper I’m giving you.

E. Board Work. (6 min)- IF TIME

[As students work, erase board. Then walk through aisles and ask individual students to put their examples on the board.] Have students display their work and explain their answers.

CLOSURE: (4 min)

Today, we learned how to write equations. What are the operations we’re going to be looking for in the words? And what’s the most important word we learned today? [IS] And what does it mean? [EQUALS]. Excellent. Next period we’re going to start solving some of these types of equations.

Objective:

TSW will learn how to formulate algebraic equations to reflect a given situation.

Assessment:

Informal:

The students will be asked to explain their answers to questions from independent practice (M).

Formal:

Independent practice (C) will be graded for accuracy and entered into grade book (D). The students will be tested on their knowledge of interpreting equations (C) on an exam on Friday (D).