r is the set of positive even integers less than 50 , and s is the set of the squares of the integers in r . how many elements does the intersection of r and s contain ?
"squares < 50 { 1 , 4,9 , 16,25 , 36,49 } s = { 1,4 , 16,36 } r = { 2 , . . . . . 48 } hence c ."
subtract(const_4, const_1)