Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
5.18 Study Guide Algebraic Expressions Learning Goals 5.18 a) b) c) d) investigate and describe the concept of variable; write an open sentence to represent a given mathematical relationship, using a variable; model one-step linear equations in one variable, using addition and subtraction; and create a problem situation based on a given open sentence, using a single variable. Vocabulary Variable Expression - mathematical phrase which can contain numbers, operators (add, subtract, multiply, divide), and at least one variable. Expressions do not contain an = sign. (Also known as algebraic expressions) example: n + 7 Variable – a letter or symbol representing a varying quantity example: n + 6 = 8 Open Sentence – a mathematical sentence which contains one or more variable and an = sign n+7=9 Examples and Explanations Problem Situation Mike had some baseball cards and his brother gave him four more 7 boxes each contained the same number of apples The cookies were split evenly among 3 friends Problem Situation Mike had six baseball cards, his brother gave him four more, and now he has 18 cards. 7 boxes, each containing the same number of apples, totaled 84 apples in all. How many cookies were baked if four friends each received three cookies? Variable Expression b+4 7a c/4 Open Sentence b + 4 = 18 7a = 84 c/4 = 3 Phrases can also be used to represent expressions Phrase four divided by a number eight more than a number seven less than a number six times a number Multiplication and Division can be represented in different forms Multiplication 8x4 8∙4 8(4) 8n Division 8÷4 8/4 8 4 Variable Expression 4÷n t+8 k–7 6n Practice at Home Continue to practice basic addition, subtraction, multiplication and division facts. It is vital that students know the basic facts in order to solve these equations. Use simple phrases and real life problem situations to create open sentences or expressions. Sample Questions 1. Which word describes the letter “p” in the expression below? 9xp A B C D whole number operation algebra variable 2. Which of these could be solved using the open sentence 7 – 2 = h? A B C D Ryan had 7 now? Ryan had 7 altogether? Ryan had 7 in all? Ryan had 7 hamsters. Each hamster had two babies. How many hamsters does Ryan have hamsters. The bought two more at the pet store. How many does he have hamsters. He gave each of them 2 treats? How many treats did he give them hamsters. He gave 2 to a friend. How many does he have left? 3. Kathleen has three times as many seashells in her collections as her friend Gabby. Gabby has 15 seashells. Which number sentence could be used to find k, the number of seashells that Kathleen has? A B C D k = 15 - 3 k = 15 + 3 k = 15 x 3 k = 15/3 4. Which of the following phrases represents the phrase “4 less than a certain number”? A B C D 4 4 n n -n +n -4 +4