25
There are no four-digit perfect squares that are palindromes.
Total number of 2-digit numbers = (99 - 9) = 90 of themEvery number that isn't a perfect square has an even number of factors.2-digit numbers that are perfect squares: 16, 25, 36, 49, 64, and 81 = 6 of themRemaining 2-digit numbers = (99 - 6) = 93 .
There is no pair of perfect squares that sums to 21. And the question is pointless if it is not about perfect squares because in that case there are infinitely many answers.There is no pair of perfect squares that sums to 21. And the question is pointless if it is not about perfect squares because in that case there are infinitely many answers.There is no pair of perfect squares that sums to 21. And the question is pointless if it is not about perfect squares because in that case there are infinitely many answers.There is no pair of perfect squares that sums to 21. And the question is pointless if it is not about perfect squares because in that case there are infinitely many answers.
There are infinitely many, just like in base 10. In any base system, the number of perfect squares is the same. Take the natural (counting) numbers 1, 2, 3, .... Squaring each of these produces the perfect squares. As there are an infinite number of natural numbers, there are an infinite number of perfect squares. The first 10 perfect squares in base 5 are: 15, 45, 145, 315, 1005, 1215, 1445, 2245, 3115, 4005, ...
25
There are no four-digit perfect squares that are palindromes.
102 = 100 which is the first possible three digit number that is a perfect square. 312 = 961 which is the last possible three digit number that is a perfect square. So there are 22 three digit positive numbers that are perfect squares.
500
Total number of 2-digit numbers = (99 - 9) = 90 of themEvery number that isn't a perfect square has an even number of factors.2-digit numbers that are perfect squares: 16, 25, 36, 49, 64, and 81 = 6 of themRemaining 2-digit numbers = (99 - 6) = 93 .
Two. 36, and 49 are perfect squares.
The smallest 5-digit integer perfect square is 10,000 = (100)2The largest 5-digit integer perfect square is 99,856 = (316)2So we want to know how many numbers that is, from 100 to 316 inclusive.It's 316 minus the first 99 = 217 of them.
Three numbers.
none
There is no pair of perfect squares that sums to 21. And the question is pointless if it is not about perfect squares because in that case there are infinitely many answers.There is no pair of perfect squares that sums to 21. And the question is pointless if it is not about perfect squares because in that case there are infinitely many answers.There is no pair of perfect squares that sums to 21. And the question is pointless if it is not about perfect squares because in that case there are infinitely many answers.There is no pair of perfect squares that sums to 21. And the question is pointless if it is not about perfect squares because in that case there are infinitely many answers.
Infinitely many. There are a 100 perfect squares.
Perfect squares have an odd number of factors. There are 31 perfect squares less than 1000.