Lesson Topic: True and False Number Sentences Lesson Objective: I can… Explain what the equality and inequality symbols include. They will determine if a number sentence is true or false based on the given symbol. Identify values for the variables in equations and inequalities that result in true and false number sentences.
Quick notes… Remember that variables represent unknown values. What you learn today will be very important to know when we get to solving equations later in this module.
Think about it this way… Equations and inequalities are like complete sentences with letters (variables) and words/phrases (expressions).
Copy down this table & let’s complete it together
Example 1 Directions: Copy down the equation or inequality & write whether it’s “true” or “false” when you substitute 3 for x x = x = x > x > x ≥ 8 For #5, would any other number work?
Example 2 Directions: Copy down the table & write if the number substituted for g results in a “true” or “false” number sentence for each empty box. Substitute g with 3g ≥ 30G ≥ 10g/2 > 2G > 430 ≥ 38–gG ≥
Discussion How are 4g = 32 and g = 8 related? How are 3g ≥ 30 and g ≥ 10 related? You can get from 4g = 32 to g = 8 by dividing both sides by 4. You can get from g = 8 to 4g = 32 by multiplying both sides of g = 8 by 4. You can get from 3g ≥ 30 to g ≥ 10 by dividing both sides by 3. You can get from g ≥ 10 to 3g ≥ 30 by multiplying both sides by 3.
Example 3 It may be helpful to visualize a number line
Continued… Try substituting 0 & 1,000 as a variable’s value.
Continued… State when the following equations and inequalities will be true and when they will be false.
Only one number can be substituted for a variable to make equations true, but several numbers can be substituted for a variable for inequalities.
Evaluate Your Learning How will you “Sharpen Your Saw”?