Numbers are also playful

1986/12/01 Etxebarria, Jose Ramon | Goñi, Jesus Mari Iturria: Elhuyar aldizkaria

• Matematika

To begin with, it seems to us a matter of justice to make known our unfortunate situation. No one has written to us. You have read it well, sir, none. Angry with remorse, nothing stronger than indifference for the lover, we have made a courageous decision: we will not give solutions to the questions we posed in the last article. As you are wicked, you are perishable to you. You will never know if we knew the solution. In this way you can taste that bitter sapor of the indifference that we have felt.

After this painful vengeance of ink, the blood has been tempered, the nerves loosened and the red eye bleached. We are ready to embark on a new mathematical adventure. On this occasion, leaving aside the questions of Logic, we return to the world of Arithmetic.

Take the calculator, paper and pen.

This is the first game.

Choose a number with three figures, one you want, like 563.

Repeat these figures in the same order forming a number of six figures:

563 Applicable regulations

Take the last number and divided by 7

563.563: 7 = 80509 is the exact ratio! ! News

Take the result and divide by 11

80509: 11 = 7319 again exact quotient, what a thing! News

Resume the result and divide by 13

7319: 13 = 563

again the exact and also the initial number, too for the body, wow! ! News

Why? Our revenge: if you want to know try it. To demonstrate that we are not completely infarcted, we warn you that you can take the resolution by investigating divisibility.

And with other figures? Look.

Here's another game.

Choose a figure that you like or that makes the biggest leap, it doesn't matter. Example 5a.

Repeat 6 times

5555

Take this number divided by 3:

555,555: 3 = 185,185

Therefore, we are included in the example above, so this number will have the properties mentioned above.

185.185 : 7 = 26.455 25.455 : 11 = 2.405 2.405 : 13 = 185

Other:

Choose a number with two figures, such as 37.

Repeat 3 times

3737

Take this number and have fun through 3 ditches:

3737: 3 = 124579

Divide the result by 7:

124579: 7 = 177979

Split result by 481

17797: 481 = 37

surprising?

Finally, an invention using the calculator:

Choose a number with three figures, but with some column, row or diagonal that appears on the keyboard.

For example: Diagonal 753 654 rows column 582

As you see, the order of figures is irrelevant.

Multiply by a figure in the right column (3, 6 or 9).

753 x 6 = 4518

This number will always be multiple of 9 because the two products are multiple of 3.

From here you can extract the following mathematical tru:

Ask to write a number that meets the first condition without you seeing the calculator. Do the same with the second and order the product.
• Request all product figures except the last one.

Then he will tell you the result given by the calculator. Because to correct the remaining figure to calculate the result, it is enough to add all the figures mentioned and calculate the missing for the next multiple of 9. The reason is clear: if a number is multiple of 9, the sum of its figures is also multiple of 9.