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The Four Signs

Part of the Inequalities & Absolute Value section of Coddy's Algebra journey. Lesson 1 of 61.

To ride the roller coaster, you must be at least 120 cm tall. 120, 150 and 200 cm can all ride.

h≥120h \ge 120

This is an inequality: one side can be bigger than the other. It has many answers.

  • x<5x < 5: less than 5
  • x>5x > 5: greater than 5
  • x≤5x \le 5: 5 or less
  • x≥5x \ge 5: 5 or more
challenge icon

Challenge

Is 30 a solution of x+15<42x+15 < 42? Put 30 in for xx: is 30+1530+15 smaller than, equal to or bigger than 42? Choose the sign.

Try it yourself

30+15  >  4230+15 \;\boxed{\phantom{>}}\; 42

Pick the sign that makes it true

All lessons in Inequalities & Absolute Value

1What an Inequality Is

The Four SignsA Picture on a LineReading It BackwardsRecap: What an Inequality Is

4Two-Step Inequalities

Two StepsSubtract, Then FlipWith a FractionA Bracket on the WayRecap: Two-Step Inequalities

7Between Two Numbers

Two Conditions at OnceSolving a ChainTwo Moves on All PartsWhen the Chain FlipsChains with FractionsRecap: Between Two Numbers

10Absolute Value Inequalities

Less Than: BetweenBetween, ShiftedGreater Than: OutsideOutside, ShiftedIsolate, Then SplitAlways or NeverRecap: Absolute Inequalities

2Adding and Subtracting

Add to Both SidesSolve, Then DrawRecap: Adding and Subtracting

5Variables on Both Sides

x on Both SidesGather Toward the LargerBrackets FirstAlways True, Never TrueRecap: Variables on Both Sides

8One or the Other

Either WorksSolving Each PartAnd versus OrRecap: One or the Other

11From Words to Inequalities

At Least, At MostMore ThanA Budget That ShrinksTwo LimitsRecap: From Words

3Multiplying and Dividing

Divide by a PositiveMultiply by a PositiveThe FlipDividing by a NegativeNegative FractionsRecap: Multiply and Divide

6Graphing Solutions

From Inequality to PictureIs the Endpoint In?A Flip on the LineRecap: Graphing Solutions

9Absolute Value Equations

Distance from ZeroThe Equation |x| = 3Distance from a PointIsolate the Bars FirstA Coefficient InsideNo Solution, One SolutionRecap: Absolute Equations

12Final Challenges

Brackets and a FlipA Chain with a FlipA Wide Absolute ValueOutside, with a FractionThe Picture at the End