1, decimal unit: divide the unit "1" into several equal parts, which is called decimal unit. That is, the numerator is 1, and the denominator is a positive integer fraction, also called unit fraction, which is recorded as1/n.
Two sevenths = two sevenths.
2. Composite number: a mathematical term that refers to a natural number that can be divisible by other numbers except 1 and itself.
Therefore, the minimum composite number is 4.
Twenty-eight sevenths = four