Four students, A, B, C and D, borrow books from the library every other day. A once every two days, b once every three days, c once every four days and d once every five days. All four people go to the library to borrow books on Monday, at least (12) days. Only four people can borrow books from the library on the same day, Friday.
definition
Addition: the operation of combining two numbers into one number.
Subtraction: when two addends and one of them are known, the operation of finding the other addend.
Multiplication: the operation of finding the product of two numbers.
Division: the operation of finding another factor by knowing the product of two factors and one of them.