It's even
Square numbers 16, 25, 36, 49, 64, 81, 100
The probability is 21/36 = 7/12
25 is odd
72 is not an odd number because it is divisible by 2. 72/2 = 36.
Only 9 and 15 are odd so the rest can be rejected. 9 is not a triangular number so only 15 is odd and a triangular number.
It's even
It is even.
25 is odd
Square numbers 16, 25, 36, 49, 64, 81, 100
The probability is 21/36 = 7/12
72 is not an odd number because it is divisible by 2. 72/2 = 36.
Even numbers are divisible by 2, and odd numbers are not. 36/2=18, so 36 is an even number.
45
71 is the 36th odd number. To find the "nth" odd number, multiply the term number (ex: 36) by two, then subtract one.
6 times 6 = 36, so yes, 36 is a square. 1+2 = 3 3+3 = 6 6+4 = 10 10+5 = 15 15+6 = 21 21+7 = 28 28+8 = 36, so yes, 36 is a triangular number
That number is 36.