Math Forum - Problem of the Week

Pick a Number

Step 1: pick a 1 digit (1-6) number and roll 1 die to record the number of rolls that it takes to get your selected number.

Step 2: pick a two digit number (11-66) and roll 2 dice and record the number of rolls to get your selected number. [Note: Read the dice from left to right as they fall on the table. For example, a 4 and a 3 would read as the number 43.]

Continue likewise with 3 and 4 dice and record the results. On a graph, plot the number of dice vs. attempts to get your selected number.

Try this Random Integer Generator when you get to 4, 5, and 6 dice.

On the Worksheet, plot the Number of Dice vs. Number of Rolls. What scale do you think is needed for the Y-axis?

Before you start, can you predict, for each number of dice, how many rolls it might take to arrive at your selected number?


  1. If you selected a 5 digit number, how many attempts would it take to get your selected number?

  2. If you selected a 6 digit number, how many attempts?

  3. How many tickets would you have to buy to win the weekly lottery?

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