Lesson 6.2.6 Writing Equations Obj. 6.EE.7

We also, wrote expressions from real-world context. Previously… We learned to write algebraic expressions from word phrases where variables stand for unknown numbers. “The sum of a number and 5” n + 5 We also, wrote expressions from real-world context.

In our last lesson… We learned that an equation is a sentence that states that two mathematical expressions are equal. x + 17 = 25 We used inverse operations to solve the equations.

Today… We will write an equation from either a verbal description or a real-world situation. The good news is that we will use the same skills that we’ve already learned to help us with our lesson.

Skills Required To write these equations from a verbal description or a real-world situation: You will need to be able to take key words or words used in everyday language and determine if the words mean to add, subtract, multiply or divide. You will also need to decide in which order the numbers and letters should be written in the equation. The only new thing is that we will need to determine what goes behind the equal sign.

can help us write equations. Remembering “KEY WORDS” can help us write equations. Go over the key words for each operation. The words that have the little symbol next to them are your “turn around words”. Point to the “Add” column and have a student name the “turn around words”. Answer: more than, added to Point to the “Subtract” column and have a student name the “turn around words” as well. Answer: less than, fewer than, subtracted from Why do some of the KEY WORDS have this symbol next to them?

Key Words for Equal ( = ) equals yields totals amounts to gives To write equations, you will need to determine what goes behind the equal sign. Here are some key words that might help. equals totals gives will be is are were yields amounts to is the same as

Let’s Try Some…

Verbal Description Writing equations from a Answers: n + 14 ½ n – 22

Guided Practice Directions: Write an expression or equation for each of the following. Use n as your variable. 14 added to a number ½ of a number decreased by 22 42 divided by a number equals 7. 5 minus twice a number is 17. Triple a number increased by 8 gives 32. Students should see the difference between writing an expression and an equation. Answers: n + 14 ½ n – 22 42 ÷ n = 7 5 – 2n = 17 3n + 8 = 32

You Try! Directions: Write an expression or equation for each of the following. Use n as your variable. A number increased by 9 yields 15 4 less than a number is 20 The quotient of thirty-nine and a number equals 3. 12 is the product of six and a number. Answers: n + 9 = 15 n – 4 = 20 39 ÷ n = 3 12 = 6n

Real-World Context Writing equations from Answers: n + 14 ½ n – 22

Guided Practice Directions: Write an equation from each real world scenario. If not specified, use a variable of your choice. Each piece of candy costs 25 cents. The price of h pieces of candy is $2.00. Suzanne made a withdrawal of d dollars from her savings account. Her old balance was $350 and her new balance is $280. A large pizza pie with 15 slices is shared among p students so that each student's share is 3 slices. Answers: .25h = 2.00 350 – d = 280 15 ÷ p = 3

You Try Directions: Write an equation from each real world scenario. If not specified, use a variable of your choice. James and Simon have a reading assignment to complete. James has read r pages and Simon has read 75 pages. Together they have read a total of 200 pages. RJ earns $7.25 per hour for bussing tables. How many hours must he work to earn $290.00? The temperature t decreases 14 degrees and is now 29 degrees. Answers: r + 75 = 200 7.25h = 290 t – 14 = 29

Writing & Solving Equations from Word Problems

Give These a Try!! Word Problem Write & Solve Equation Answer Sarah started her day with a full bag of apples. After making apple pie where she used 3 apples, she noticed that she had 12 apples remaining in the bag. How many apples did Sarah begin the day with? Before his birthday party, Wilson had 4 video games in his collection. After he received his birthday presents, he noticed that he was up to a collection of 15 games. How many games did Wilson receive for his birthday? Answers: x – 3 = 12 x = 15 4 + x = 15 x = 11 9x = 72 x = 8 Bethany bought 9 new tank tops. Each of the tank tops cost the same amount. If Bethany spent a total of $72, how much did each tank top cost?

Give These a Try!! Word Problem Write & Solve Equation Answer Justin has 23 pairs of sneakers. This is 14 more than his friend Nelson. How many pairs of sneakers does Nelson have? At a restaurant, Mike and his three friends decided to divide the bill evenly. If each person paid $13 then what was the total bill? Answers: x + 14 = 23 x = 9 x/4 = 13 x = 52

Closure Statement Today, we combined several skills that we’ve learned from previous lessons and used them to write equations from verbal descriptions and real-world scenarios. Once an equation is written, you can solve the equation using inverse operations to find unknown values.

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