Finding the Odd one out from the given set of numbers makes a very interesting brain teaser. Here I am posting some riddles in which one has to find which number is odd one among the others. All numbers except one follow a certain pattern or rule which exactly one number does not follow. So your task is to find that number which stands out from the group.
I have posted the answers to these brain teasers later at the end of this post with reasoning. One may think differently and may come up with an alternative answer. Please do post your answers in the comment section of this post along with your reasoning.

Q1.
(a). 128   (b). 902    (c). 191     (d). 083     (e). 740  (f). 754

Q2.
(a). 761   (b). 853   (c). 642    (d).431  (e). 654  (f). 945

Q3.
(a).  147   (b). 337   (c).  179  (d).953  (e). 769  (f). 113

Q4.
(a). 196   (b). 289   (c). 729   (d).144  (e). 243  (f). 625

Q5.
(a). 6   (b). 15   (c). 24   (d).33  (e). 44  (f). 42

Q6.
(a). 14916   (b). 25364964   (c). 81100121144   (d).14453646

Q7.
(a). 27   (b). 64     (c). 125   (d).216   (e). 243

Q8.
(a). MQUY   (b). GKOS   (c). DGJM  (d).JNRV

Q9.
(a). 4527  (b).6739   (c).7845    (d).9851  (e). 2418 (f). 6765

Q10.
(a). 6682   (b). 2668   (c). 8266   (d).6826  (e). 8662

Don't forget to checkout Odd One Out Puzzles as mentioned below
List of Odd One Out Puzzles

1. Spot the Different Picture Brain Teasers for teens with answers: These the Picture Odd One Out Puzzles in which three puzzle images are given in each of the puzzles. Your challenge is to find which puzzle image is different.

2. Picture Brain Teasers to find which Picture is different: These are very interesting Picture Brain Teasers for Kids in which one has to find the Odd One Out Picture.

3. Tough Odd One Out Picture Puzzles for Teens and Adults: Checkout these Odd One Out Picture Puzzles in case you are looking for tough Picture Puzzles.

4. Picture Puzzles for Teens With Answers: There are lots of different types of Picture Puzzles to twist your mind along with Odd One Out Picture Puzzles.

The answers to these Mathematical Odd ones out puzzles are given below. I have hidden the answers so that one does not see the answer inadvertently. To look at the answer of a particular brain teaser, do select the text between that numbered puzzle till the next number.
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A1. 754 is the odd one, the sum of all the digits of the number is 11. Only in 754 sums of digits is 16.

A2. 654  is odd as in all other numbers sum of digits at the unit place and at tens place is equal to the digit at hundreds of places.

A3. 769 is odd as all other numbers are prime numbers.
A4.  243  is odd as all other numbers are perfect squares but 243 is not a perfect square of any number.
A5. 44,  is odd as all other numbers are multiples of 3. But 44 is not.

A6. 14453646  is odd as all other numbers are written as shown below, but 14453646 doesn't follow the pattern.
(a). 14916   =              1²2²3²4²
(b). 25364964   =        5²6²7²8²

A7. 243   is odd as all other numbers are a perfect cube

A8. DGJM is odd as all others are step count of alphabets by 4

A9. 6765, as in other numbers pattern is as follows:
(a). 4527 = 4+5=9x3=27 so no,is 4527( sum of the first two digits x3)
(b).6739=  6+7=13x3=39

A10. (e). 8662, in others every time number on one's place is moving one step forward anticlockwise but 8662 doesn’t follow the series.

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Here is the answer to the 12th Brain Teaser Question of the post titled "Simple Math Riddles for Teens and Kids with Answers to Twist your Brain".
We have hidden this answer to avoid any spoiler. Do select the text below to read the answer.
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Answer is 206. If abc x def = g then g = (a+b+d+e)(c+f).