Number Theory

 233, 239, 241 are the prime numbers between 230 and 250.

40 - 3 = 37 is a prime number.

41 is a prime number.

17, 41, 29 are prime numbers.

Between 20 and 30, there are only two prime numbers 23 and 29. Therefore, 23 x 23 + 29 x 29 = 529 + 841 = 1370

All of the above are pairs of co-prime numbers. 51 = 17 x 3 x 1 53 = 53 x 1 H.C.F. = 1 Therefore, it is a pair of co-prime numbers.

When 256 is divided by 2, we get 128 as a result. 128 is divisible by 2. Thus, 128 is an even number.

25 is an odd number.

There are 5 prime numbers (601, 607, 613, 617, 619) between 600 and 620. 

There are 4 prime numbers (151, 157, 163, 167) between 150 and 170,  

Prime numbers between 50 and 60 are 53 and 59. Sum = 53 + 59 = 112

1433 is a prime number because it has only two factors, i.e. 1 and 1433.

1979 is a prime number because it has only two factors, i.e. 1 and 1979 (number itself).

There are 3 prime numbers (71, 73, 79) between 70 and 80. 

987 is not a prime number because it has more than two factors.