The Interior — Mathematics

Inequalities

A math sentence whose answer is a whole stretch of the number line. Write one from words — at least, at most, more than, fewer than — graph it with an open or closed circle, solve it like an equation, and learn the one move that flips the sign, and why. Study cards, hints, a practice quiz at three levels, and four workshop activities that check themselves.

← Math, every band

Start Here

Start here

One answer, or a whole stretch

An equation has exactly one answer. Here it is: x = 5.

Four things people get wrong

People often think…

Subtracting a negative flips the symbol.

People often think…

A negative answer means you flip the symbol.

People often think…

“At least 8” means fewer than 8.

People often think…

5 < x shades to the left, because the arrow points left.

Solve it, then draw it

Watch one

Solve 3x + 2 ≤ 14.

  1. Subtract 2 from both sides.
  2. 3x ≤ 12.
  3. Divide by 3. Positive, so no flip.
  4. x ≤ 4. Filled circle at 4, shade left.
One sentence, then you move on

How do you know whether to use an open circle or a filled one?

Last one — then you're done here

Why does dividing by a negative turn the symbol around?

Your practice never leaves this device. There is no account and no sign-in. Your work is saved in this browser only, and you can erase it whenever you want.
Your practice record — saved on this device

This is your record of the module on screen — it stays here and goes nowhere. Independent means you got it right on the first tap; supported means you got it after the explain-and-retry, or marked ‘I had it’ on a revealed answer. Both count, and neither is a grade. If your teacher asks, copy the row or show them this screen.

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Level
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Independent
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Supported
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Hints used
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Cards studied
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Lab
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Traps met
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Explained in own words
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Confidence
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The answer key is for a teacher: it prints only from here, for the unit on screen. Print the study packet prints the study pages and a blank quiz — never the answers.