The first, smallest, and only odd prime gap is 1 between the only even prime number, 2, and the first odd prime, 3. All other prime gaps are even. There is only one pair of gaps between three consecutive odd natural numbers for which all are prime. These gaps are g2 and g3 between the primes 3, 5, and 7.
Girls usually start their periods between the ages of 10 and 16. Most girls start when they're around 12. As everyone develops at different rates, there's no right or wrong age for a girl to start. Your periods will start when your body is ready, and there's nothing you can do to make them start sooner or later. If you haven't started your periods by the time you're 16, visit your doctor for a check-up.
One day, you'll begin to bleed from your vagina, and that's your period. It means that your body is healthy and normal. Most girls have their first period when they're between 9 and 15 years old. Your period may start around the time it started for other people in your family, like your mom or sisters.he menstrual cycle is the time from the first day of one period to the first day of the next. A normal menstrual cycle can be as short as 21 days or longer than 35 days. For most women, it lasts 25 - 30 days. But it's common for your cycle to vary from month to month. Here are the basics: 1  You have two ovaries.