Chickenpox (Chicken Pox) , also known as Varicella, is a very contagious infection caused by the varicella zoster virus. In several parts of the world it is just known as varicella. Patients develop a blister-like rash, which first appears on the face and trunk, and then spreads throughout the body.
Modular arithmetic. Time-keeping on a clock gives an example of modular arithmetic. Modular arithmetic, sometimes also called clock arithmetic, is a way of doing arithmetic with integers. Much like hours on a clock, which repeat every twelve hours, once the numbers reach a certain value, called the modulus, they go back to zero. People talked about modular arithmetic in many ancient cultures.
Time-keeping on this clock uses arithmetic modulo 12. A familiar use of modular arithmetic is in the 12-hour clock, in which the day is divided into two 12-hour periods. If the time is 7:00 now, then 8 hours later it will be 3:00.ongruence relation. Modular arithmetic can be handled mathematically by introducing a congruence relation on the integers that is compatible with the operations of the ring of integers: addition, subtraction, and multiplication.