This is a fun math trick that helps reinforce the basic math skills of multiplication and short division. For this particular math set, we will work with the number 19. After working eight multiplication problems and eight division problems, when the math trick is worked correctly, you will not only begin with the number 19, you will end with the number 19 as well.
Please note: The goal is for your classroom students or home schooling children to use their own brainpower rather than a calculator.
How the math trick works
Take any number and write it down. For the sake of this example, we will work with the number 1.
8 Multiplication Steps:
Multiply that number 1 by 2.
Multiply that product of 2 by 3.
Multiply that product of 6 by 4.
Multiply that product of 24 by 5.
Multiply that product of 120 by 6.
Multiply that product of 720 by 7.
Multiply that product of 5,040 by 8.
Multiply that product of 40,320 by 9.
Our final product is 362,880.
8 Short Division Steps:
Using short division, divide that final product of 362,880 by 2.
Divide that divisor of 181,440 by 3.
Divide that divisor of 60,480 by 4.
Divide that divisor of 15,120 by 5.
Divide that divisor of 3,024 by 6.
Divide that divisor of 504 by 7.
Divide that divisor of 72 by 8.
Divide that divisor of 9 by 9.
Our final divisor is 1.
Trick: Notice that the final answer is the same as the original number you began with. For this example, we began with the number 1 and we ended with the number 1.
How the slideshow works
The slideshow is set up so that you can have your students work the math step slide by slide. The answer to each multiplication or short division problem will appear on the following slide. The entire math set with correct answers are revealed on the last two slides.
History of the math trick and name
Please note: If you study the example in Slide #1, you will see why the term lollipop is used. Since many people lick a lollipop up and down, you can see that the multiplication facts are worked in the downward direction and the division facts are worked in the upward direction.
I learned about this process at a workshop I took back when I taught fourth grade during the 1981-1982 school year. The location was in University City, Missouri (near St. Louis).
Turn this math activity into a competitive game
The term Olympics comes in should you decide to turn this activity into a competitive game. During that school year and during the years I taught fifth grade in Hawkins County, TN and in Chattanooga, TN, the students competed to see who could finish this activity first. I had the entire math set written in a notebook. The students had the option to come up and check their work at any point to make certain their products or divisors were correct or wait until they completed the entire set.
Checking their work early paid off if they had an incorrect product or divisor as they did not have as many problems to re-work. Those students who got all the way to the end of the math set and did not have the correct answer felt regret that they did not check their work along the way. Regardless if they finished first or last, all students still needed to complete the entire math set since they needed the practice and to get a good grade.