The abacus is believed to have been developed in the ancient Near East in the third millennium BCE. An abacus consists of a series of thin parallel bars set into a rectangular frame, usually made of wood. Each bar contains a number of beads that slide along its length. Individuals use the beads as number counters and use the abacus to perform addition, subtraction, multiplication, and division.
How to Hit Puberty Faster. Puberty is that time of life when a childâs body matures into the body of an adult. Puberty for boys starts usually between the ages of 9 and 14 years old. The symptoms of puberty in boys include enlargement of testicles and penis, growth of underarm hair, facial and pubic hair, deepening of voices and a growth spurt.
Puberty doesn't happen all at once â it happens in stages. Guys usually start puberty later than girls, when they're around 10 to 12 years old. Some start sooner and others later. You may continue to go through puberty changes until you're 20 years old. A guy may show some signs of puberty at an early age (like a voice that's starting to crack) but may not show other signs of puberty until years later (like growing facial hair).