The term 'kind of number' can refer to a variety of different types of numbers. The crossword solutions for this term include FAX (3 letters), REAL (4 letters), ATOMIC (6 letters), SERIAL (6 letters), MACH (4 letters), PRIME (5 letters), ODD (3 letters), EVEN (4 letters), WRONG (5 letters), and ORDINAL (7 letters). FAX refers to a type of communication technology that sends documents over telephone lines. REAL is a type of number that includes all rational and irrational numbers. ATOMIC numbers are used to identify elements in the periodic table. SERIAL numbers are used to identify unique items, such as products or vehicles. MACH numbers measure the speed of sound in a particular medium. PRIME numbers are numbers that are only divisible by themselves and one. ODD and EVEN numbers are two categories of integers that are distinguished by their parity. WRONG numbers are numbers that are incorrect or inaccurate. Finally, ORDINAL numbers are used to indicate position or rank in a series.