Probability Models Worksheets, Grade 7 (7.SP.C.7) – Free PDF + Answer Key

First page of the probability models practice worksheet

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PDFs print on US Letter paper. Free for classroom and home use.

Step-by-step math videos on the Math With Mr DJ YouTube channel →

Key idea

Build the model from the equally likely outcomes. For two dice those are the 36 pairs, not the 11 totals. Count how many pairs give each total, and divide by 36. Then compare the model with data, judging discrepancies by their size.

Sample problems

How many ways can two dice total 3?
How many ways can two dice total 6?
How many ways can two dice total 12?
Find P(total 6).

Common mistakes to watch for

Answered 6 or 60, giving counts rather than probabilities.
Concluded the die is unfair because the counts are not all 10. A model predicts approximate frequencies, and exact agreement would be more suspicious than these deviations.
Said both dice are unfair because neither gave exactly 10 each. The question is always the SIZE of the discrepancy, not its existence.

The answer key explains each one, so you can tell what a wrong answer means.

How to use this set

Teach with the slides (about 15 minutes), or watch the video together.
Practice with the worksheet. Questions climb from fluency to application to reasoning.
Check understanding with the exit ticket, and send the homework home.
Mark with the answer key — each answer shows the steps and the most likely mistake.