Scott got a little nutty one evening and wanted to figure out the possibility of ever getting a duplicate worksheet. So he crunched some numbers.

He crunched the numbers for our popular worksheet entitled Telling Time. It has 9 problems on the page. He included only these selection options:

• What time is it?
• Draw the hands on the clock.

• 1 minute increments.

Speaking in round numbers, there are 9.89 x 10²⁵ different worksheets that could be generated. That is a 9 followed by 25 zeroes, or 98,900,000,000,000,000,000,000,000 different worksheets.

If you’re interested in the math behind that figure, I can give you the details. There are 720 minutes on a 12-hour clock. So there are 720 possibilities for the first problem. Since duplicate problems are removed by the software, we have 719 possibilities for the second problem. Then 718 possibilities for the third problem. Continue that for 9 problems. Then multiply that by 2 for the options of ‘What time is it?’ vs. ‘Draw the hands on the clocks.’ That gives us:

720 x 719 x 718 x 717 x 716 x 715 x 714 x 713 x 712 x 2 =

(I’m thankful for calculators!)

98,905,804,935,121,008,618,393,600 different worksheets.

Just for Telling Time.

Another popular worksheet is Multiplication: Single-Digit, Vertical. If you only select one factor on the left (say, a 7) and you leave 0-9 selected on the right (so the student is practicing “the sevens”), there are 1.216 x 10¹⁷ or 121,645,100,408,832,000 different worksheets that could be generated just with “the sevens.”

The odds of you ever seeing a duplicate worksheet?

I’d say they’re pretty small.

–Denise

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