# Write a system of equations to represent the situations

The essential concepts students need to demonstrate or understand to achieve the lesson objective Given a real-world constraint or condition, identify values that fit. Ordering items from a school canteen menu is the context for this unit. There are four sessions only in this unit. It is important, however, that the number of sessions is increased, if appropriate, to ensure the concepts are fully understood.

It is also important to ensure that quality time is given to discussions, with student explanations being encouraged and valued. Understand that an unknown amount or number can be represented with a symbol: Write expressions using variables.

Activity 1 Begin the session by discussing lunch options in your school. Display Attachment 1the canteen menu for Kiwi School. Read it together checking prices of random specific items using the price list in the box at the bottom of the menu. Note that some differences in daily special prices may reflect the size of portions and that only some students buy their food from the canteen.

Write on the class modelling book: Ask what is a quicker way to write this? How many orders were placed? Have the students complete the form either individually or in pairs, then share and discuss their results. Activity 2 Discuss the strategies student used to complete the form.

Write examples of equations, highlighting that when they were multiplying they were finding the value of unknown amounts. When we solve equations with symbols for unknown amounts we have to find out what number the symbol stands for.

Make pencils and paper available. Pose this problem for student pairs to discuss and answer: What numbers could the symbols for the unknowns in these equations stand for?

Have students pair-share their solutions. Encourage the students to use the language: Discuss ideas as a class, highlighting these key points: Write 3n on the class modelling book.

Have students discuss and explain its meaning. Highlight the fact that the multiplication symbol does not need to be shown. Explain that the prices are on the canteen menu, but that the lunch orders for Tuesday are shown differently.

The number of items ordered. Discuss the strategies student used to complete the form. Write examples of equations for selected problems, using the order form context.

How many were ordered? How do we know? Conclude the lesson by recording on the class modelling book and discussing the kinds of symbols we have been using: Agree that these symbols together make it possible to express our mathematical thinking and to solve problems.

Write word problems of real life situations and express these with equations that include a variable. Solve single step whole number equations that include a variable. Activity 1 Refer to the order forms for Monday and Tuesday, from Session 1. Review key learning from this session. Ask students to discuss in pairs what this expression means 3 more than an unknown amount.

Accept and discuss a range of possible scenarios.Problems involving numerical and algebraic expressions and equations (7th grade) Use a bar model to write and solve equations An updated version of this instructional video is available. Write a system of equations.

Describe your variables. Let x represent the number of multiple-choice questions and y represent the number of openended response questions. WRITING Describe three ways to solve a system of linear equations. In Exercises 4 – 6, (a) write a system of linear equations to represent the situation.

Then, answer the question using (b) a table, (c) a graph, and (d) algebra. Write an inequality of the form x > c or x to represent a constraint or condition in a real-world or mathematical problem. Recognize that inequalities of the form x > c or x represent solutions of such inequalities on number line diagrams.

Where can situations when the value of one variable depends on the value of another be found in real life? an algebraic rule or an equation into the graphing calculator for each. Show the equations in Y. Have the students write the equations on bottom of the journal page.

Help students work with manipulatives to represent real-world. Students explore many problems for which they must write and graph pairs of equations leading to the generalization that finding one point of intersection is the single solution to the system of equations.

Writing and Solving Equations From Real World Problems -