Sunny days

AFTER travelling in a relative way faster than light and arriving on the previous night, Ms Bright thinks that she is always right.

Under this state of mind, she is running up and down the pitch in Wankhede Stadium when she meets a gentleman who introduces himself as Sunil Gavaskar. He has been an international cricketer whose best friend on the pitch has always been his pocket calculator. Presently, he looks stumped by a problem which has occupied his mind since tea.

He tells Ms Bright that he has lost his pocket calculator and a company wants to distribute Rs 36,51,67,484 among the Mumbai XI after the match, but only if no decimal currency is involved. Sunny says, "I would not know how to solve the problem even if I had my best friend with me."

Ms Bright peeps into the fourth dimension for a moment and tells Sunny that he should not worry because the figure is evenly divisible by 11, so, no decimal currency will change hands.

"Howzzatt?" asks Sunny.

"Find out for yourself; the figure is 36,51,67,484. Add the first, third, fifth, and seventh digits and so on (3 + 5 + 6 + 4 + 4 = 22), that is every alternate number beginning from the first. Now, add every alternate number beginning from the second (6 + 1 + 7 + 8 = 22). If the difference, including 0, is divisible by 11, then so is the number. In this case, 22-22 = 0, so, 36,51,67,484 is evenly divisible by 11," says the woman.

Sunny: Is 11 a special number?

Ms Bright: In a way, yes, you can directly write down the answer to any number multiplied by 11. Take for example the number 51236 X 11. First, write down the number with a zero in front of it.

The zero is necessary so that the rule is simpler. Draw a line under the number. Add the neighbour or as I call it the "The Right Hand Side Friend".

lLook at the digit 6 in the "units" position of the number. Since there is no number to the right of it, you cannot add its "neighbour" to it, so, just write down 6 below the 6 in the units column.

lFor the "tens" place, add the next figure 3 to the its "Right Hand Side Friend" (6). Write the second digit of the answer: 9 below the 3.

lFor the "hundreds" place, add the next figure 2 to the its "Right Hand Side Friend" (3). Write the third digit of the answer: 5 below the 2.

lFor the "thousands" place, add the next figure 1 to the its "Right Hand Side Friend" (2). Write the fourth digit of the answer: 3 below the 1.

lFor the "ten-thousands" place, add the next figure 5 to the its "Right Hand Side Friend" (1). Write the fifth digit of the answer: 6 below the 5.

lFor the "hundred-thousands" place, add the 0 before the figure to its "Right Hand Side Friend" (5). Write the last digit of the answer: 5 below the 0. That’s it...11 X 051236 = 563596.

Ms Bright: Learn to practice these methods, you will survive even where there are no calculators Sunny.

Sunny: Thanks, you are bright.

Ms Bright: Yeah, but how did you know my name?

— Aditya Rishi