1) 6/7 is arationalnumber because it can be expressed as a ratio of two integers. Since all rational numbers are real numbers, 6/7 is also arealnumber.

3) 0 is awhole numberand aninteger. It is also arational number(you could write 0 as 0/1) and areal number.

8) 26.1 is arationalnumber (you could write it as 261/10). Rational numbers can also be decimals that terminate, like this one.

14) is anirrationalnumber. It's decimal equivalent would be a non-repeating, non-terminating decimal. All square roots of positive integers that are not perfect squares are irrational numbers. The numbers and e are also irrational numbers. Since all irrational numbers are also real numbers, is also arealnumber.

19) 894,000 is a natural number, a whole number, an integer, a rational number, and a real number.

A couple of other points:

- A number cannot be BOTH rational and irrational. It is one or the other.

- Note the hierarchy of these sets of numbers. Example: all integers are rational numbers, but not all rational numbers are integers.