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.
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!
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
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.
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!
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.
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!