Presentation on theme: "Halloween Warm-Up Paul has two dozen Halloween cookies. He will eat three cookies on Sunday. On every day that follows, he will eat a number of cookies."— Presentation transcript:
1 Halloween Warm-UpPaul has two dozen Halloween cookies. He will eat three cookies on Sunday. On every day that follows, he will eat a number of cookies that is one greater than the day before. On what day will he find that he doesn’t have enough cookies to follow this procedure?
2 Answer Thursday Sun -3 Mon- 4 Tues- 5 Wed -6 18 cookies eaten = 6 cookies left over, but on Thursday he needs to eat 7 cookies to continue his pattern.
4 Rules to RememberWhen solving an equation, the goal is to get the variable by itself.Addition and Subtraction are inverse operations. (opposites)Multiplication and Division are inverse operations. (opposites)
5 Don’t ForgetThe equation is like a balance scale. Whatever you do to one side of the equation must be done to the other side of the equation.
6 How to solve two-step equations “Undo” the operations in the reverse order of the order of operations.You are using the work back-words strategyIn order of operations we do multiplication or division first, then addition and subtraction. When solving an equation we do the opposite!
7 Integer Rules to Remember Adding IntegersSame sign= add and keep the signDifferent sign = subtract and keep the sign of the larger numberSubtracting IntegersKeep, Change, ChangeFollow the rules for additionMultiplying and Dividing IntegersSame Sign = Positive AnswerDifferent Sign = Negative Answer
8 Let’s Try One… 3x + 2 = 23 - 2 -2 21 3x = 21 3 3 x = 7 213x = 21x = 7The problem contains addition and multiplication. Which one do we undo 1st?
9 Another Example -2y – 7 = 3 +7 +7 10 -2y = 10 -2 -2 y = -5 10-2y = 10y = -5The problem contains subtraction and multiplication. Which one do we undo 1st?
10 Last Example -3c + 9 = 3 -9 -9 -6 -3c = -6 -3 -3 c = 2 -6-3c = -6c = 2The problem contains addition and multiplication. Which one do we undo 1st?