## Thinking Mathematically (6th Edition)

Given B={x|x belongs to N where 3 $\leq$ x <10} From the given question. The given set represents the natural numbers which are greater than equal to 3 but less than 10 Those numbers are 3,4,5,6,7,8,9. The set contains 7 elements. The cardinal number for each set is formed by calculating the number of elements in each set. Therefore the cardinal number for given set B is n(B) = 7.