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.
There are many signs of puberty in girls. Keep in mind that these stages may appear gradually and it may take three to four years for your child to cycle through all the phases of puberty. In general, boys will go through puberty at some point between the ages of 9 and 14. Girls may begin between the ages of 8 and 12. Share these signs with your tween daughter so she knows what to expect.