1 1-6 Solving Equations by Adding & Subtracting Aim: Aim: How can we write and solve equations using addition and subtraction? CCSS: 6.EE.7

2 Aim: Aim: How can we write and solve equations using addition and subtraction? Warm up Vocabulary Review: A ____________________ to an equation is any value that makes the equation true. Simplify each expression (-4) (-7) (-5)

3 The Addition Property of Equality If you add the same number to each side of an equation, the two sides remain equal. 10 = 5(2), so = 5(2) = 3(7), so = 3(7) + 9

4 The Subtraction Property of Equality If you subtract the same number from each side of an equation, the two sides remain equal. 10 = 5(2), so = 5(2) = 4(8), so = 4(8) - 10

5 Solving by Adding Solve for k and r: -2 = k - 14 r - 32 = -5

6 Solving by Subtracting Solve for q and z: 24 + q = 100 z + 45 = -65

7 Which Strategy Do we Use? An airplane climbs a height of 7,900 ft during a flight. At that moment, the airplane’s altitude is at 13,220 ft. What was the airplane’s original altitude? (HINT:) First write the equation that can represent this situation.

8 Think, Turn & Talk 1. Vocabulary Check: How is an expression different from an equation? 2. Your friend made y bracelets. After she gave away 4 of them, she had eight bracelets left. Write an equation to model the situation. Use Mental Math: Find whether -3 is a solution. 3. a + 4 = 7 4. w - 7 = c = 4 6. z - 3 = p = 4

9 Activity Lab: Number Square A number square is a square table with the same number of rows and columns. Each row, column and main diagonal in the square has the same sum. Example: The following Number Square has the sum of 15 in every row, column and diagonal. Number Square of

10 Complete the Number Square   Task: Write and solve an equation to find each missing value in the Number Square below.   Step One: Use a row, column or diagonal with no variables to find the sum.   Step Two: Use the same sum to write an equation for all the other possible sums with variables. 10 2b-2 ac 01-4

11 Exit Ticket A small separate piece of paper. Solve each equation for the given variable. (Hand In) 1. w = h - (-7) = = m = b + (-100)