## What is the 9 trick in math?

A Mathemagical Trick Start by thinking of a number, any number.

Now, multiply that number by 9.

If the result is a multi-digit number, add its digits together to come up with a new number.

If that new number is still a multi-digit number, add its digits together to come up with yet another new number..

## Why is 28 the perfect number?

A number is perfect if all of its factors, including 1 but excluding itself, perfectly add up to the number you began with. 6, for example, is perfect, because its factors — 3, 2, and 1 — all sum up to 6. 28 is perfect too: 14, 7, 4, 2, and 1 add up to 28.

## What is the weirdest number?

Examples. The smallest weird number is 70. Its proper divisors are 1, 2, 5, 7, 10, 14, and 35; these sum to 74, but no subset of these sums to 70. The number 12, for example, is abundant but not weird, because the proper divisors of 12 are 1, 2, 3, 4, and 6, which sum to 16; but 2 + 4 + 6 = 12.

## What is the most famous number?

10 Famous NumbersThe Greek letter pi represents a value of approximately 3.14159, the ratio between the circumference and diameter of a circle. … e, known as Euler’s number, is approximately 2.71828 and is another nonrepeating, nonterminating number. … 10100 is a Googol. … 0 has nothing to it. … 1 is the first counting number.More items…

## How does the number trick work?

One type of number trick involves adding, subtracting, multiplying, or dividing by a starting number and subtracting the original number in such a way that each participant always arrives at a certain number: Think of a number between 1 and 100. Multiply your number by 4.

## Why is 1089 a magic number?

1089 is widely used in magic tricks because it can be “produced” from any two three-digit numbers. This allows it to be used as the basis for a Magician’s Choice. … Reverse the digits, and subtract the smaller from the larger one. Add to this result the number produced by reversing its digits.

## How do you find a magic number?

This number represents the number of wins by the leading team or losses by the trailing team which will eliminate the trailing team. The largest elimination number among the non-first place teams is the magic number for the leading team. Then the magic number for Team B to be eliminated is 162 + 1 – 96 – 62 = 5.