Mathematics number starter – Fun with a calculator 111,111,111 x 111,111,111 = 12,345,678,987,654,321

Before a Calculator lesson as a starter I like getting learners to have fun with their resource. I get them to enter the following into their calculators and watch their amazement when they see the answer.

111,111,111 x 111,111,111 = 12,345,678,987,654,321

A great extension to this is asking the question “Why does this happen.?”


You can also  start with 11*11 then 111*111 and so on and then ask learners to spot patterns predict 111 111 111* 111 111 111!!

Categorised as: Funny | Learner | Mathematics | Number | Teacher


  1. erin says:

    Hey I have a question I know that 111,111,111×111,111,111= 12,345,678,987,654,321 but why is that that every time I put the equation I to my calculator I don’t get that answer? I checked it several times and even used a different calculator and still received the same results…the answer I got was 1.234568e16. Why am I getting this answer? And what does the “e” mean. Thank you.

    • Jason says:

      Your calculator is using scientific notation.
      The e means x 10^
      The operation that you are doing on your calculator is too large for the screen. Most calculator screens only show 8-10 digits. The answer is too large to display on your calculator.

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