227,229
239,241
269,271
281,283
227,229
239,241
269,271
281,283
2 and 5.
Neither 170 nor 190 have twin prime factors.
Sixteen primes.
The twin primes to 300 are 3 and 5, 5 and 7, 11 and 13, 17 and 19, 29 and 31, 41 and 43, 59 and 61, 71 and 73, 101 and 103, 107 and 109, 137 and 139, 149 and 151, 179 and 181, 191 and 193, 197 and 199, 227 and 229, 239 and 241, 269 and 271, 281 and 283.
There are 168 prime numbers under 1,000 . There are also 25 primes under 100, 62 primes under 300, and 95 primes under 500
500
200
There are 5 multiples of 18 between 200 and 300. (An even number divisible by 9 is any number divisible by 18).
500
300
200
200 + 100 = 300