Fun with numbers! :)
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:2, x3+1 trick (made by Tymen)
If it is a even number you divide by two
If it is an odd number you multiply it by three and add one
Eventually it will always end in a cyclus of 4,2,1,4,2,1,4,2,1........
Examples:
8 --> 4 --> 2 --> 1 --> 4 --> 2 --> 1
9 --> 28 --> 14 --> 7 --> 22 --> 11 --> 34 --> 17 --> 52 --> 26 --> 13 --> 40 --> 20 --> 10 --> 5 --> 16 --> 8 --> 4 --> 2 --> 1 --> 4 --> 2 --> 1
256 --> 128 --> 64 --> 32 --> 16 --> 8 --> 4 --> 2 --> 1 --> 4 --> 2 --> 1
27--> 82--> 41--> 124--> 62-->31--> a lot of steps --> 20--> 10--> 5--> 16--> 8--> 4-->2 -->1 --> 4 -->2 --> 1
Be a mind reader (made by Jarco)
Ask somebody to do this, but he shouldn’t tell you the numbers he used.
Step 1: take a number consisting out of 3 whole numbers, with the highest number first and the lowest number last, for example 431, 732 or 987.
Step 2: take the same number and subtract it from the first number but then turned around, so 431-134, 732-237 and 987-789.
Step 3: ask for the first number of the answer (or the last), and you will know exactly what the answer was the person had: 431-134=297, 732-237=495 and 987-789=198
How it works: if you do all steps correct, the answer will always have a nine in the middle and the first and last number together will also always be nine, so if the person you asked to do this did it correct, you always will guess the answer correct, and you will look like you can read minds.
If it is a even number you divide by two
If it is an odd number you multiply it by three and add one
Eventually it will always end in a cyclus of 4,2,1,4,2,1,4,2,1........
Examples:
8 --> 4 --> 2 --> 1 --> 4 --> 2 --> 1
9 --> 28 --> 14 --> 7 --> 22 --> 11 --> 34 --> 17 --> 52 --> 26 --> 13 --> 40 --> 20 --> 10 --> 5 --> 16 --> 8 --> 4 --> 2 --> 1 --> 4 --> 2 --> 1
256 --> 128 --> 64 --> 32 --> 16 --> 8 --> 4 --> 2 --> 1 --> 4 --> 2 --> 1
27--> 82--> 41--> 124--> 62-->31--> a lot of steps --> 20--> 10--> 5--> 16--> 8--> 4-->2 -->1 --> 4 -->2 --> 1
Be a mind reader (made by Jarco)
Ask somebody to do this, but he shouldn’t tell you the numbers he used.
Step 1: take a number consisting out of 3 whole numbers, with the highest number first and the lowest number last, for example 431, 732 or 987.
Step 2: take the same number and subtract it from the first number but then turned around, so 431-134, 732-237 and 987-789.
Step 3: ask for the first number of the answer (or the last), and you will know exactly what the answer was the person had: 431-134=297, 732-237=495 and 987-789=198
How it works: if you do all steps correct, the answer will always have a nine in the middle and the first and last number together will also always be nine, so if the person you asked to do this did it correct, you always will guess the answer correct, and you will look like you can read minds.
Finger multiplication of 6,7,8,9,10
Place your fingers as in the image and consider the value of fingers in each hand to be 6, 7, 8, 9 and 10 - in the order from small finger to thumb.
(made by Gitte)
Example
Consider the multiplication of 7 × 8.
Make the finger numbered 7 in the left hand to touch the finger numbered 8 in the right hand.
Step 1:
Now in the left hand, count the finger which is touching (7) and the ones below that = 2 fingers
Similarly in the right hand, count the finger which is touching (8) and the ones below that = 3 fingers
Add the above counted fingers = 2 + 3 = 5 fingers
Multiply the number by 10 = 5 × 10 = 50 -----> (1)
Step 2:
In the left hand, count the fingers above the touching finger = 3 fingers
Similarly in the right hand, count the fingers above the touching finger = 2 fingers
Multiply both = 3 × 2 = 6 -----> (2)
Step 3:
Add (1) and (2),
= 50 + 6 = 56
So, the answer for 7 × 8 = 56 which is easily found through the above trick.
Note:
If there is no finger above the considered (touched) finger, then consider the value as zero (0).
Place your fingers as in the image and consider the value of fingers in each hand to be 6, 7, 8, 9 and 10 - in the order from small finger to thumb.
(made by Gitte)
Example
Consider the multiplication of 7 × 8.
Make the finger numbered 7 in the left hand to touch the finger numbered 8 in the right hand.
Step 1:
Now in the left hand, count the finger which is touching (7) and the ones below that = 2 fingers
Similarly in the right hand, count the finger which is touching (8) and the ones below that = 3 fingers
Add the above counted fingers = 2 + 3 = 5 fingers
Multiply the number by 10 = 5 × 10 = 50 -----> (1)
Step 2:
In the left hand, count the fingers above the touching finger = 3 fingers
Similarly in the right hand, count the fingers above the touching finger = 2 fingers
Multiply both = 3 × 2 = 6 -----> (2)
Step 3:
Add (1) and (2),
= 50 + 6 = 56
So, the answer for 7 × 8 = 56 which is easily found through the above trick.
Note:
If there is no finger above the considered (touched) finger, then consider the value as zero (0).
Multiplication tricks (made by Gitte)
1. Multiplication trick 7x11x13
Step 1: Ask your friend to write a three digit number.
Lets assume a number, 539
Step 2: Now ask your friend to multiply the number with 7, 11 and 13.
Step 3: Before your friend says the result, you can reveal it much faster.
The answer is 539539
Note: When you multiply any three digit number with 7, 11 and 13, result will be always twice the original number.
For example, 786 x 7 x 11 x 13 = 786786
2Multiplication trick 3x7x13x37
Step1:
Think of a 2 digit number.
Step2:
Multiply it with x3x7x13x37.
Ex: Number: 45, Answer: 454545
Multiplication trick 11x9091
Step1:
Think of a 5 digit number.
Step2:
Multiply it with 11.
Step3:
Multiply it with 9091.
Ex: Number: 12345,Answer:1234512345
1. Multiplication trick 7x11x13
Step 1: Ask your friend to write a three digit number.
Lets assume a number, 539
Step 2: Now ask your friend to multiply the number with 7, 11 and 13.
Step 3: Before your friend says the result, you can reveal it much faster.
The answer is 539539
Note: When you multiply any three digit number with 7, 11 and 13, result will be always twice the original number.
For example, 786 x 7 x 11 x 13 = 786786
2Multiplication trick 3x7x13x37
Step1:
Think of a 2 digit number.
Step2:
Multiply it with x3x7x13x37.
Ex: Number: 45, Answer: 454545
Multiplication trick 11x9091
Step1:
Think of a 5 digit number.
Step2:
Multiply it with 11.
Step3:
Multiply it with 9091.
Ex: Number: 12345,Answer:1234512345
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I will guess your age! (made by Anne Fleur)
With some mathematical help I'll guess your real age.
You just need to follow my instructions:
If you want, you can use a calculator.
Step 1:
Pick a number between 1 and 10
Step 2:
Multiply your chosen number by 2
Step 3:
Add 5
Step 4:
Multiply the result by 50
Step 5:
If you have already had your birthday this year: add 1767,
if you haven't then add 1766
Step 6:
Now subtract the 4-digit year you were born in
(eg minus 2002)
Now you should only have a three-digit number left...
THE INCREDIBLE RESULT:
The first number is the one you chose at the beginning...
The other numbers are your age!
With some mathematical help I'll guess your real age.
You just need to follow my instructions:
If you want, you can use a calculator.
Step 1:
Pick a number between 1 and 10
Step 2:
Multiply your chosen number by 2
Step 3:
Add 5
Step 4:
Multiply the result by 50
Step 5:
If you have already had your birthday this year: add 1767,
if you haven't then add 1766
Step 6:
Now subtract the 4-digit year you were born in
(eg minus 2002)
Now you should only have a three-digit number left...
THE INCREDIBLE RESULT:
The first number is the one you chose at the beginning...
The other numbers are your age!
The trick with the table of nine is made by Silke