# Fast Math - Square Roots

In this quiz the answers change every time you play! Solve these randomised square root problems as fast as you can!
Answer must correspond to highlighted box!
Too easy? Try the harder version: Up to 200 squared
Quiz by Stewart
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Last updated: November 3, 2019
 First submitted November 3, 2019 Times taken 19,876 Average score 70.0% Rating 4.38
2:30
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+10
Level 65
Nov 10, 2019
I made a Fast Math - Roots Quiz in August, not that anyone cares.
+15
Level 68
Nov 10, 2019
But yours wasn't randomised, and is cube roots too. This is just square roots.
+2
Level 52
Nov 13, 2019
I am the damn champion. 100% first time with 8 seconds left.
+3
Level 69
Dec 28, 2019
1:24 left
+17
Level 58
Jan 6, 2020
did it in 43s on my first try. simple trick: estimate the first digit by ignoring the last two digits and taking the square root, then guess the last digit by looking at the last digit.
+2
Level 72
Apr 7, 2020
Can I call you '819' for short?....... anyway you are correct with your tip, I got 19/20 having a go your way........ i don't know why it works ...... but it does!
+1
Level 62
Apr 24, 2020
I had a similar trick, just guessed numbers using the first 3 digits and using the last digit to see if the root was odd.
+5
Level 65
Jun 23, 2020
No estimation required:

>100 means it's 10+

>400 means it's 20+

>900 means it's 30+

>1600 means it's 40+ and

>2500 means it's 50+

And the last digit:

1 means either 1 or 9

4 means 2 or 8

5 means 5

6 means 4 or 6 and

9 means 3 or 7

+1
Level 74
Jul 8, 2020
ben415 nice tip, got them all using this method.
+2
Level 86
Apr 10, 2020
Easy, Tyger
+1
Level 35
Aug 23, 2021
who

+1
Level 33
Dec 22, 2019
100% first try with 19 seconds left i could have done it faster but for somereason i got stuck on one
+16
Level 85
Apr 7, 2020
Now you'll remember that the square root of one is one.
+3
Level 81
Apr 6, 2020
There's a lot of time on the clock - got 100% with a minute left and a lot of guessing. It's easy to just go in order of lower to higher and guess very quickly.
+1
Level 68
Apr 7, 2020
The time is the same as other "fast math" quizzes. 2:30 with 20 questions! Remember if this is too easy you can always try the harder version in the description!
+1
Level 62
Apr 6, 2020
Funny!
+1
Level 34
Apr 16, 2020
1st try ma bois
+1
Level 60
May 18, 2020
0:33 .. phew
+1
Level 65
Jun 23, 2020
1:27 remaining héhé
+1
Level 57
Jun 30, 2020
1:54 remaining on first try
+1
Level 67
Jun 23, 2020
Wasn't expecting to be able to do this one, but did it with a lot of guesswork lol. Out of interest, anyone got any good techniques?
+2
Level 68
Jun 23, 2020
I feel like my technique is what I remember from school. The final digit of your answer determines the final digit in the squared number. 1 -> 1, 2 -> 4, 3 -> 9, 4 -> 6, 5 -> 5, et cetera. Once you know any square ending in a 4 must have come from a 2 or a 4, you're down to only several guesses that make sense. Then you can just keep in mind that if it's under 100, the answer must be under 10. If it's under 400, under 20. Under 900, under 30. Under 1600, under 40. Under 2500, under 50. I used this method and solved it with a couple minutes remaining on my first try.
+2
Level 77
Jun 23, 2020
I'm terrible at math, but I lucked out in getting clues for answers that ranged mostly from 37 through 51, so after I worked one out it was easy to look at the last digit of the remaining clues and fill in the others based on the first answer. Then I had four really easy ones, which left me plenty of time for the few I actually strugged with. Phew!
+3
Level 67
Jun 23, 2020
Maybe this is why I majored in English ...
+1
Level 54
Jun 27, 2020
Great quiz! Thanks for including the top bar, looks amazing this way!
+1
Level 28
Dec 11, 2020
pajace
+1
Level 55
Mar 21, 2021
got them all in 42 secs
+1
Level 68
Oct 10, 2021
there could be a harder version of this quiz where the answers you've already got don't stay shown, so you can't use them to help estimate the remaining ones. would be challenging but sounds like some people in these comments would like the challenge (and before anyone suggests it, i don't have the quizmaking skills to do this myself).
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