Try This Algebra Problem

Algebra Level 1

What number fits into the center square?

5 0 20 15

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Calvin Lin by Calvin Lin

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21 solutions

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Calvin Lin Staff
Jun 26, 2014

The answer is 5. The numbers are arranged in sequential order 1, 2, 3, 4, 5, 6, 7, 8, 9.

66 Helpful 0 Interesting 0 Brilliant 0 Confused

At first I thought 5, then I thought that was too obvious, I looked again and found that every opposite number going through the middle added up to 10 i.e 1,9=10 7,3= 10 etc. So I chose 10 thinking this a more suitable answer.............

Lee Woods - 6 years, 11 months ago

This question was intentionally meant to be easy / immediate. Thanks for sharing your opinion of why 10 could be an answer. I've removed 10 from the available options, so that it is easier for others to chose from.

Calvin Lin Staff - 6 years, 11 months ago

Can you take 0 out too b/c the same situation arrives if you add 0

Frank Jackson - 6 years, 7 months ago

Actually this was a mind scratching question.........Ha ha ha ha.!!!

PUSHPESH KUMAR - 6 years, 11 months ago

I also thought 5 was too obvious but chose it anyways

Paul Kazadi - 6 years, 11 months ago

intermediate? Trololololololololololol

Kaden Bea - 6 years, 11 months ago

@Kaden Bea – He said immediate not intermediate! XD

Aditya Dhawan - 6 years, 11 months ago

Just a fyi in case you had intended to, you didn't remove 10 from the options.

Dorian Thiessen - 6 years, 10 months ago

dont be confused every time ok brother

Rozi Khan - 6 years, 10 months ago

I Also immediately thought the answer was 5 but that seemed to easy. I also noted that the numbers opposite the ? Added up to 10 (9 +1, 8+2). So I picked 0, as every other number would keep that relation (the sum of all numbers through the center would remain the same). So I picked 0.

Sam Rozans - 6 years, 3 months ago

How is this algebra???

Alan Zhou - 6 years, 11 months ago

This question is poorly phrased in multiple aspects. I understand the purpose after seeing the solution, but the question is somewhat vague.

Ahmed Abdelqader - 6 years, 11 months ago

Problem extremely stupid and ambiguous, if 5 is the choice, it is a simple sequence, but it can be 0, then the sum in cross-shape or X-shape will be always 10. This problem should not to be here. The problem is marked in ALGEBRA category, but it's a sequence. Where's the algebra? Ridiculous!

Eduardo Porto Teixeira - 6 years, 11 months ago

The diagonal no 1 and 9 add to 10. 2+8=10 and 6+4=10. So I got little confused and stamped 0 from my keyboard.

Chitranshu Vashishth - 6 years, 11 months ago

But sum from diagonally, horizontally and vertically comes to be 10 if we put zero and for 5 it comes as 15 so 0 might be another answer isn't it

Nitin Srivastava - 6 years, 5 months ago

This is a very amazing problem :D

Alan Hu - 6 years, 11 months ago

wow >>> its very hard >>> the next question will be count to ten

Ibrahim Mohammed - 6 years, 11 months ago

Sometimes we make a mistake when things are too obvious!!

Ali Bahramishad - 6 years, 11 months ago

finally a decent amount of points :D

Shad Ali - 6 years, 11 months ago

This question doesn't really make much sense at all.

Yerdua Hos - 6 years, 9 months ago

I agree with 10

Smeet Patel - 6 years, 11 months ago

ya me to same

Suri Babu - 6 years, 10 months ago

lol is that a question ??????!!!!!!!!!!!!!!hahaha

Lakshya Jain - 6 years, 4 months ago

i was thiking this hard, because afraid of trick but...

Hamidah Nurfallah - 6 years, 11 months ago

it is too much easy for anyone

Muhammad Hassan - 6 years, 11 months ago

man!!! what an obvious question and i was trying everything from matching the diagonals n all..:(

Sanya Munjal - 6 years, 11 months ago

oh god really?

Sagar Limaye - 6 years, 11 months ago

yeah!! but i guess most of the people were doing that...

Sanya Munjal - 6 years, 11 months ago

ahh.. there was nothing challenging its an obvio ans...!!!

Anand Ralegankar - 6 years, 11 months ago

La respuesta no es del todo correcta, o es la pregunta la que no está bien formulada: las dos respuestas son posibles.

Uriel Arias - 6 years, 3 months ago

5is my answer

Macky Mallo - 6 years, 11 months ago

i thought the answer would be 5.if the answer was 5, then the sum of numbers (diagonally & straight line through the center) would be 10

Swapnil Saha - 6 years, 11 months ago

hey man too easy.....took just a second

Anish Mukherjee - 6 years, 11 months ago

Serial number is 1 2 3 4 5 6 7 8 9

Aditta nishad - 6 years, 10 months ago

Lol 5 is too obvious but still i chose it xD

Dexter Val Campillanos - 6 years, 10 months ago

I don't understand

Mohammed Aboelshiekh - 6 years, 11 months ago

What a simple question!!

Anagha Nair - 6 years, 8 months ago

i took much time to solve it

Rakib Hasan Pamin - 6 years, 11 months ago
Rishikesh Sorte
Jul 16, 2014

This was a very boring question

19 Helpful 0 Interesting 0 Brilliant 0 Confused
Giovana Benevides
Jun 27, 2014

a resposta é o número 5 pois eles estão em uma sequencia é o número que se encaixa é o 5

4 Helpful 0 Interesting 0 Brilliant 0 Confused

Translation from Portuguese: The answer is number 5 because they are in a sequence is the number that fits is 5. Thanks google translate

David Lee - 6 years, 11 months ago

Thank you, I was too lazy to use Google translate.

Zakaria Sellami - 6 years, 11 months ago

i thought 5 was the ANS

Ambreen Malik - 6 years, 11 months ago
Mehul Arora
Dec 5, 2014

What the.................Question was this?!?

2 Helpful 0 Interesting 0 Brilliant 0 Confused
Palash Som
Oct 18, 2014

sometimes such easy questions make me scare 8-)

2 Helpful 0 Interesting 0 Brilliant 0 Confused

the no. is missing in bw 1-9 is 5

2 Helpful 0 Interesting 0 Brilliant 0 Confused
Hassan Raza
Jul 30, 2014

How stupid is that

2 Helpful 0 Interesting 0 Brilliant 0 Confused
Billy Joven
Jul 22, 2014

Its too obvious that 5 is the answer at first, cause based on my experience. Algebre is not this easy as it looks >.< But in the end i find that 5 is the answer..

2 Helpful 0 Interesting 0 Brilliant 0 Confused
Taha Sawar
Jul 6, 2014

The number increases horizontally by adding 1 So 4 + 1 = 5 They also increase vertically by adding 3 So 2 + 3 = 5

2 Helpful 0 Interesting 0 Brilliant 0 Confused
Tristan Shin
Jul 4, 2014

Another way this problem could be solved is by seeing that every row, column, and diagonal should form an arithmetic sequence. Taking this into account, the middle row should be 4,5, 6, and the middle number should be 5.

1 Helpful 0 Interesting 0 Brilliant 0 Confused
Akshay Shiva
Dec 7, 2014

do not think too high okay ? they arranged in a sequence 123456789

0 Helpful 0 Interesting 0 Brilliant 0 Confused

its not possible to place a double digit number in this sequence of numbers. its obvious that it cant be 0 it would be nonsense. so whats left in the choices? "5" thats why i answered 5, the first answer that seems to be correct. :)

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Kumar Alok
Oct 6, 2014

the number is arranaged in sequential order 1,2,3,4,5,6,7,8,9

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Carl Harvey Jayme
Sep 24, 2014

First Column 1+3 = 4 ,, 4+3=7

2nd Column 2+3 = 5 ,, 5+3 = 8

3rd Column 3+3 = 6 .. 6+3 = 9

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Muhammad Faizan
Sep 23, 2014

5 is missing from 1 to 9 integers

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Abak Chowdhury
Jul 20, 2014

The answer is 5. The numbers are arranged in sequential order 1, 2, 3, 4, 5, 6, 7, 8, 9.

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Muhammed Gousla
Jul 8, 2014

5 its about the order of numbers 1,2,3,4,5,6,...

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Joshua Arejola
Jul 8, 2014

Besides being in sequential order from left to right then up to down, another solution could be is that if you pick a line of three numbers (e.g. 1, 4, 7), the sum of the numbers on two ends (e.g. 1 and 7) when divided by 2 would give the number in the middle (e.g. 1+7=8; 8/2=4).

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Prince Mishra
Jul 6, 2014

first number plus third number divided by 2 we get 6+4/2=5 or 8+2/2 =5

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Krishna Garg
Jul 6, 2014

this is insequence ,so middle no is 5 Ans K.K.GARG,India

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Girish Kumar
Jul 4, 2014

The answer is 5... Sum of c1 & c2 is 12 & 18 respectively.... so that to maintain the difference same (i.e, 3) the answer should be 5...

0 Helpful 0 Interesting 0 Brilliant 0 Confused

Its 10 :) I thot 5 would be the answer but after a deep thinking on the numbers which adds like (1+9, 3+7,8+2),i got the answer 10 :)

Ashrafun Misty - 6 years, 11 months ago

yeah ! the sum of the opposite numbers are 10., that is why, when finding the middle value we have to divide it by two .. so the answer is 5

Raffy Bacquiano - 6 years, 11 months ago

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