Slope From Two Points | Math Mystery Worksheets | Grades 7–9 | Formula Practice

Five detective cases drill the slope formula until the order of the points stops mattering — students work out the slope of the line through each pair, write it in the box beside it, match it to a suspect, and cross suspects off until one is left standing. This no-prep, printable, self-checking Math Mystery keeps 7th, 8th and 9th graders engaged and works for math centers, bell work, homework, early finishers, substitute/relief days, spiral review, and test prep. The cases build deliberately: whole-number pairs first, then negatives, then pairs listed back to front.

Quick Details

Skill: Finding slope from two points with the slope formula · Grades: 7–9 · Format: 5 mysteries + full answer keys (printable PDF) · Theme: Survey and mapping

The 5 Mysteries

The Survey Pegs — The crew drives two pegs for every boundary line, and somebody pulled them up overnight and hammered them back in the wrong places.

The Falling Tide — Every gauge along the estuary reads lower as the tide runs out, so the slopes come out negative.

The Mine Shaft Log — Depths below ground are written as negative numbers, and two markers are logged for every tunnel.

The Satellite Grid — The tracking station puts itself at zero, so half of every reading is negative.

The Cold Case File — A clerk wrote some pairs down back to front, and the listed order must not change — students have to handle the subtraction correctly either way.

Why Teachers Love It

Zero prep — print and teach. The built-in answer keys make every case self-checking, so students get instant feedback and stay motivated. The sequence targets the two mistakes students actually make — sign errors with negative coordinates, and subtracting the pairs in inconsistent order — rather than repeating easy pairs five times.

Skills Covered

Applying the slope formula to two ordered pairs, working with negative coordinates, keeping the subtraction consistent in numerator and denominator, simplifying the resulting fraction, and interpreting positive and negative slope in context — plus logical reasoning and deductive elimination as students rule suspects out clue by clue.

What's Included

Printable one-page mystery worksheets, coordinate pairs set out clearly, suspect line-ups, complete answer keys with the villain marked, and student instructions — all in one PDF.

Best Used For

Slope formula practice in math centers, bell work, homework, early finishers, substitute/relief days, spiral review, and test prep for grades 7–9.

More From This Line

Browse every Math Mystery pack, or pair it with Finding Slope and Combining Like Terms.