# Test your mathematical intelligence (math IQ quiz)

Which number should come next in these series ? Difficulty increases after each question.
Quiz by AlbertK
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Last updated: July 21, 2016
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 First submitted July 21, 2016 Times taken 3,267 Average score 57.1% Rating 4.44 Report this quiz Report
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 Hint Answer 1, 2, 3, 4, 5, ? 6 3, 6, 9, 12, 15, ? 18 3, 6, 12, 24, 48, ? 96 4, 5, 7, 10, 14, ? 19 4, 6, 10, 18, 34, ? 66 8, 15, 24, 35, 48, ? 63 17, 25, 32, 37, 47, ? 58
 Hint Answer 25, 54, 83, 112, 141, ? 170 35, 24, 19, 32, 39, 28, 23, ? 36 15, 27, 42, 84, 168, ? 336 31, 71, 12, 52, 92, ? 33 59, 14, 19, 29, 40, 44, 52, 59, ? 73 43, 54, 31, 17, 22, 16, ? 14 142, 562, 586, 9016, 14201, 64562, ? 701867
+4
Level 20
Dec 10, 2018
I got 13/14 in first try!very very happy
+2
Level 48
Jul 20, 2019
expain 33 and the last one.
+2
Level 43
May 10, 2020
For 33, the easiest way to explain is switch the tens and ones places and its just adding 4. Not sure about the last one though...
+1
Level 58
Sep 18, 2020
Add 40 (31->71), subtract 59 (71->12), add 40 twice (12->52->92), subtract 59 again (92->33)
+2
Level 77
Jan 2, 2021
The way I read it was that the first digit is incremented by 4 each time; if it overflows, increment the last digit
+1
Level 37
Sep 29, 2021
Can anyone explain the second to last please? The 43, 54, 31…..
+2
Level 52
Oct 1, 2021
it is a sum of products of opposite digits of preceding and following number

43, 54 --> (4*4) + (3*5) = 31

54, 31 --> (5*1) + (4*3) = 17

31, 17 --> (3*7) + (1*1) = 22

...

22, 16 --> (2*6) + (2*1) = 14

+1
Level 55
Jan 12, 2023
Can anybody explain the last one please?
+2
Level 60
Aug 1, 2023
I think it's this: given a number XYZ, form the number (X+1)(Y+2)(Z+3) (not multiplying here, literally just putting the numbers in those positions), then reverse the result. E.g.:

142 -> (1+1)&(4+2)&(2+3) = 265, now reverse to get 562.

562 -> 685 -> 586

586 -> 6109 -> 9016.

and so on.

+1
Level 40
Mar 20, 2023
Can someone explain the last one please? Thx
+1
Level 60
Aug 2, 2023
See my response to qza
+1
Level 32
Aug 24, 2023
Can someone explain the one where the answer is 73?
+1
Level 50
Sep 29, 2023
given a number (XY), the next number is X+Y+XY (i'm not multiplying X by Y, its quite literally the number they make together, the og number it gives you. This apparently starts right after the first 59, so it goes as:

59 (5+9=14), so 14 is the starting point.

14 (1+4+14=19), 19 (1+9+19=29), 29 (2+9+29=40), 40 (4+0+40=44), 44 (4+4+44=52), 52 (5+2+52=59), and at the end it goes: 5+9+59=73